gistfile1.js

var nodes = 0, 
unique_handlers = [];
jQuery && jQuery('*').each(function() {
var ev = jQuery(this).data('events')
if (ev) {
    for (var e in ev) {
        eh_arr = ev[e];
        nodes+=eh_arr.length;
        for (var j=0, l=eh_arr.length; j<l; j++) {
           eh = eh_arr[j].handler, sb = false;
           for (var k=0, m=unique_handlers.length;k<m; k++) {
               if (unique_handlers[k] === eh) {
                    sb = true;
                    break;
               }
           }
           sb || unique_handlers.push(eh);
        }
    }
}
})

console.info('There are ' + unique_handlers.length + ' unique event handlers bound to', nodes, 'nodes.')

Counts all event handlers attached to DOM nodes with jQuery bind (requires jQuery 1.4), while checking them for uniqueness. For performance (esp. in web applications) you should have smallest number of event handlers attached to fewest amount of nodes. Consider using named functions instead of anonymous functions and event delegation to reduce both numbers.