The main part of Javascript that drives xkcd's "Time" comic (http://xkcd.com/1190/), deobfuscated and annotated. The bulk of the script seems to be an implementation of EventSource - which, while important, is not terribly interesting for our purposes, so I've omitted it here. After some Googling around, I am in fact fairly certain that the Even…

xkcd_time.js

//This event appears to ping xkcd's servers when various things happen
//Probably for serverside logging/analytics/debugging/statistics
function ping_event(evt_name) {
    (new Image).src = "http://xkcd.com/events/" + evt_name
}
//This function ouputs debug info into the javascript console if the URL has a "#verbose" anchor appended
function log() {
    location.hash == "#verbose" && console.log.apply(console, arguments)
}
//A list of event streams to choose from at random, for load balancing
var loadbalance_urls = ["http://c0.xkcd.com", "http://c1.xkcd.com", "http://c2.xkcd.com", "http://c3.xkcd.com", "http://c4.xkcd.com", "http://c5.xkcd.com", "http://c6.xkcd.com", "http://c7.xkcd.com"];
try {
    //Choose a stream and initialize and EventSource watching it
    var baseurl = loadbalance_urls[Math.floor(Math.random() * loadbalance_urls.length)],
        evturl = baseurl + "/stream/comic/time?method=EventSource",
        s = new EventSource(evturl);
    log("connecting to event source:", evturl);

    //Connect functions to listen for certain events, mostly diagnostic
    //Ping xkcd's server when the stream is opened
    s.addEventListener("open", function (msg) { ping_event("connect_start") }, false);
    //Ping xkcd's server and log to the console on an error
    s.addEventListener("error", function (msg) { log("connection error", msg); ping_event("connect_error") }, false); 
    //Log pings and events from xkcd's server in the console
    s.addEventListener("comic/time/ping", log, false);
    s.addEventListener("comic/time", log, false);

    //This is the meat of the function - responds to "comic/time" events from xckd's event streams
    var first_event = true;
    s.addEventListener("comic/time", function (msg) {
        //Parse the message from the stream
        var data = JSON.parse(msg.data);
        //Grab the image so we can change it
        var img = document.getElementById("comic").getElementsByTagName("img")[0];
        //If it's the first ping, display the image immediately
        //otherwise delay it by a random number of seconds
        //Between zero and the maximum spread defined in the event
        //This is presumably another load-balancing mechanism
        var delay = first_event ? 0 : Math.round(Math.random() * data.spread);

        //Change the image and log as such
        log("waiting", delay, "seconds before displaying comic", data.image);
        setTimeout(function () { img.src = "http://imgs.xkcd.com/comics/time/" + data.image }, delay * 1e3);

        //It's not the first event any more
        first_event = false
    }, false);

    //Also respond to requests for page reloads
    //Presumably this is in case Randall needs to update the javascript, which he did several times (this is version 7)
    s.addEventListener("comic/time/reload", function (msg) {
        //Also introduce a random delay here, again likely for load-balancing
        //So not everyone reloads the page at once
        var delay = Math.round(Math.random() * 55);

        //Reload the page, whee!
        log("reloading in", delay + 5, "seconds");
        setTimeout(function () {
            ping_event("reloading");
            setTimeout(function () { location.reload() }, 5e3)
        }, delay * 1e3)
    }, false)
} catch (err) {
    //If we have javascript errors, send them back to xkcd's servers
    ping_event("js_error")
}

z_time07.js

//For reference
//The entirety of the original source, beautified/initially deobfuscated
(function (e) {
    "use strict";

    function t() {
        this.data = {}
    }
    function n() {
        this.listeners = new t
    }
    function r(e) {
        setTimeout(function () {
            throw e
        }, 0)
    }
    function i(e) {
        this.type = e
    }
    function s(e, t) {
        i.call(this, e), this.data = t.data, this.lastEventId = t.lastEventId
    }
    function g(e, t) {
        var n = Number(e);
        return (n < 1 ? 1 : n > 18e6 ? 18e6 : n) || t
    }
    function y(e, t, n) {
        try {
            typeof e[t] == "function" && e[t](n)
        } catch (i) {
            r(i)
        }
    }
    function b(t, r) {
        function B() {
            L = d, N !== null && (N.abort(), N = null), C !== 0 && (clearTimeout(C), C = 0), S.readyState = d
        }
        function j(e) {
            var t = L === p || L === h ? N.responseText || "" : "",
                n = null;
            if (L === h) {
                var r = f ? t !== "" ? N.getResponseHeader("Content-Type") : "" : N.contentType;
                if (r && v.test(r)) {
                    L = p, T = !0, x = u, S.readyState = p, n = new i("open"), S.dispatchEvent(n), y(S, "onopen", n);
                    if (L === d) return
                }
            }
            if (L === p) {
                t.length > k && (H = !0, T = !0);
                var o = 0,
                    a = t.indexOf("\r", k),
                    l = t.indexOf("\n", k);
                while (a !== -1 || l !== -1) {
                    a === -1 || l !== -1 && l < a ? (o = l, l = t.indexOf("\n", o + 1)) : (o = a, a = t.indexOf("\r", o + 1));
                    var m = t.slice(k, o),
                        B = D;
                    D = t.slice(o, o + 1) === "\r", k = o + 1;
                    if (!B || m.length !== 0 || D) {
                        _.push(m);
                        var j = _.join("");
                        _.length = 0;
                        if (j !== "") {
                            var I = "",
                                q = j.indexOf(":", 0);
                            q !== -1 && (I = j.slice(q + (j.slice(q + 1, q + 2) === " " ? 2 : 1)), j = j.slice(0, q)), j === "data" ? A.push(I) : j === "id" ? O = I : j === "event" ? M = I : j === "retry" ? (u = g(I, u), x = u, b < u && (b = u)) : j === "retryLimit" ? b = g(I, b) : j === "heartbeatTimeout" && (w = g(I, w), C !== 0 && (clearTimeout(C), C = setTimeout(R, w)))
                        } else {
                            if (A.length !== 0) {
                                E = O;
                                var U = M || "message";
                                n = new s(U, {
                                    data: A.join("\n"),
                                    lastEventId: O
                                }), S.dispatchEvent(n), U === "message" && y(S, "onmessage", n);
                                if (L === d) return
                            }
                            A.length = 0, M = ""
                        }
                    }
                }
                k !== t.length && (_.push(t.slice(k)), k = t.length)
            }
            H && P === 0 && (H = !1, P = setTimeout(F, 80)), L !== p && L !== h || !(e || k > 1048576 || C === 0 && !T) ? C === 0 && (T = !1, C = setTimeout(R, w)) : (L = c, N.abort(), C !== 0 && (clearTimeout(C), C = 0), x > b && (x = b), C = setTimeout(R, x), x = x * 2 + 1, S.readyState = h, n = new i("error"), S.dispatchEvent(n), y(S, "onerror", n))
        }
        function F() {
            P = 0, j(!1)
        }
        function I() {
            j(!1)
        }
        function q() {
            j(!0)
        }
        function R() {
            C = 0;
            if (L !== c) {
                j(!1);
                return
            }
            if (navigator.onLine === !1) {
                C = setTimeout(R, 500);
                return
            }
            if (m && e.document && (e.document.readyState === "loading" || e.document.readyState === "interactive")) {
                C = setTimeout(R, 100);
                return
            }
            N.onload = N.onerror = q, N.mozAnon === undefined ? N.onprogress = I : N.onreadystatechange = I, T = !1, C = setTimeout(R, w), k = 0, L = h, A.length = 0, M = "", O = E, _.length = 0, D = !1, N.open("GET", t + ((t.indexOf("?", 0) === -1 ? "?" : "&") + "lastEventId=" + encodeURIComponent(E) + "&r=" + String(Math.random() + 1).slice(2)), !0), N.withCredentials = o, N.responseType = "text", f && N.setRequestHeader("Accept", "text/event-stream"), N.send(null)
        }
        t = String(t);
        var o = Boolean(a && r && r.withCredentials),
            u = g(r ? r.retry : NaN, 1e3),
            b = g(r ? r.retryLimit : NaN, 3e5),
            w = g(r ? r.heartbeatTimeout : NaN, 45e3),
            E = r && r.lastEventId && String(r.lastEventId) || "",
            S = this,
            x = u,
            T = !1,
            N = new l,
            C = 0,
            k = 0,
            L = c,
            A = [],
            O = "",
            M = "",
            _ = [],
            D = !1,
            P = 0,
            H = !1;
        r = null, n.call(this), this.close = B, this.url = t, this.readyState = h, this.withCredentials = o, R()
    }
    function w() {
        this.CONNECTING = h, this.OPEN = p, this.CLOSED = d
    }
    t.prototype = {
        get: function (e) {
            return this.data[e + "~"]
        },
        set: function (e, t) {
            this.data[e + "~"] = t
        },
        "delete": function (e) {
            delete this.data[e + "~"]
        }
    }, n.prototype = {
        dispatchEvent: function (e) {
            var t = String(e.type),
                n = this.listeners,
                i = n.get(t);
            if (!i) return;
            var s = i.length,
                o = -1;
            while (++o < s) {
                var u = i[o];
                try {
                    u.call(this, e)
                } catch (a) {
                    r(a)
                }
            }
        },
        addEventListener: function (e, t) {
            e = String(e);
            var n = this.listeners,
                r = n.get(e);
            r || n.set(e, r = []);
            var i = r.length;
            while (--i >= 0) if (r[i] === t) return;
            r.push(t)
        },
        removeEventListener: function (e, t) {
            e = String(e);
            var n = this.listeners,
                r = n.get(e);
            if (!r) return;
            var i = r.length,
                s = [],
                o = -1;
            while (++o < i) r[o] !== t && s.push(r[o]);
            s.length === 0 ? n["delete"](e) : n.set(e, s)
        }
    }, s.prototype = i.prototype;
    var o = e.XMLHttpRequest,
        u = e.XDomainRequest,
        a = Boolean(o && (new o).withCredentials !== undefined),
        f = a,
        l = a ? o : u,
        c = -1,
        h = 0,
        p = 1,
        d = 2,
        v = /^text\/event\-stream;?(\s*charset\=utf\-8)?$/i,
        m = /AppleWebKit\/5([0-2][0-9]|3[0-4])[^\d]/.test(navigator.userAgent);
    w.prototype = n.prototype, b.prototype = new w, w.call(b), l && (e.EventSource = b)
})(this),
function () {
    function t(e) {
        (new Image).src = "http://xkcd.com/events/" + e
    }
    function n() {
        location.hash == "#verbose" && console.log.apply(console, arguments)
    }
    var e = ["http://c0.xkcd.com", "http://c1.xkcd.com", "http://c2.xkcd.com", "http://c3.xkcd.com", "http://c4.xkcd.com", "http://c5.xkcd.com", "http://c6.xkcd.com", "http://c7.xkcd.com"];
    try {
        var r = e[Math.floor(Math.random() * e.length)],
            i = r + "/stream/comic/time?method=EventSource",
            s = new EventSource(i);
        n("connecting to event source:", i), s.addEventListener("open", function (e) {
            t("connect_start")
        }, !1), s.addEventListener("error", function (e) {
            n("connection error", e), t("connect_error")
        }, !1), s.addEventListener("comic/time/ping", n, !1), s.addEventListener("comic/time", n, !1);
        var o = !0;
        s.addEventListener("comic/time", function (e) {
            var t = JSON.parse(e.data),
                r = document.getElementById("comic").getElementsByTagName("img")[0],
                i = o ? 0 : Math.round(Math.random() * t.spread);
            n("waiting", i, "seconds before displaying comic", t.image), setTimeout(function () {
                r.src = "http://imgs.xkcd.com/comics/time/" + t.image
            }, i * 1e3), o = !1
        }, !1), s.addEventListener("comic/time/reload", function (e) {
            var r = Math.round(Math.random() * 55);
            n("reloading in", r + 5, "seconds"), setTimeout(function () {
                t("reloading"), setTimeout(function () {
                    location.reload()
                }, 5e3)
            }, r * 1e3)
        }, !1)
    } catch (u) {
        t("js_error")
    }
}();