whatdoesitdo.js

(function a() {
    /* (function(package) {
     *  (function(a) {
     *      "use strict";
     *      var a\u005f = package;
     *      with(a_)
     *          this && a();
     *  })(a);
     * })();
     */

    var code = "";
    var match;
    var re = /[ /]\* (.+)$/gm;

    while(match = re.exec(a)) {
        code += match[1];
    }

    try {
        var package = {a: a};
        eval(code);
    } catch(ex) {
        console.log(/SyntaxError: (.+)/.exec(ex.stack)[1]);
        return;
    } finally {
        console.log(";-)");
    }
})();

https://gist.github.com/brian-hannay/5733214
Another what does it do... Interesting how you parse the function as a string :P