Here is some jQuery for a search box that I expect is actually an antipattern, and am sure there is a much better solution for that I would love to be pointed towards:
I frequently use the following approach, a simple function to execute a callback, after the user has stopped typing for a specified amount of time::
$(selector).keyup(function () {
  typewatch(function () {
    // executed only 500 ms after the last keyup event.
  }, 500);
});
Implementation:
var typewatch = (function(){
  var timer = 0;
  return function(callback, ms){
    clearTimeout (timer);
    timer = setTimeout(callback, ms);
  };
})();
I think this approach is very simple, and it doesn't imply any global variables.
For more sophisticated usages, give a look to the jQuery TypeWatch Plugin.
Have a look at the excellent Text Change Event plugin from Zurb, purveyors of the highest quality jQuery goods.
This is a more good way to do it, without using the plugin:
var timeout;
$('input[type=text]').keypress(function() {
if(timeout) {
    clearTimeout(timeout);
    timeout = null;
}
timeout = setTimeout(myFunction, 5000)
})