Animation.js, keep it short, keep it simple!
Programmers love inheritance, they name their children like inherited classes, they implement interfaces and do other nasty things involving parent relations 
Not all of them: Bernie Sumption hates inheritance.
Not all of them: Bernie Sumption hates inheritance.
I was putting together my new home page the other day, and decided that the chicken could use some lipstick in the form of one of those new-fangled animated accordion widgets. I checked several different libraries and found them all to be lacking. In particular, they don’t seem to realise that inheritance is evil, and must be destroyed. By providing base classes for an effect and requiring users to subclass it to make new effects, they create a proliferation of classes and make it too hard to create new effects that the library designer hasn’t thought of (scriptaculous gets round this by thinking of every effect you might want, which is why it is so large).Being a developer that loves a good challenge he simply made his own animation library: Animation.js. The code you get is very minimalistic and … beautiful. Programmers love not having to write too much, they hate verbosity, so keep the code they have to write short and they’ll love you
ex2 = new Animator({
duration: 1200,
interval: 400,
onComplete: function() {$('ex2Target').innerHTML += "Bing! ";}
})
ex2.addSubject(updateButton);
function updateButton(value) {
$('ex2Target').innerHTML += " Badda ";
}
ex13 = Animator.apply($('ex13Button'), "background-color: #3F9"); // ta da!
It also had the side benefit to proof that people would trust their passwords into a meta service like this, but that is another issue.
Meebo just had a large update that they call 
icon in your IM window to “pop†the window out of the main meebo browser (don’t forget to disable any pop-up blockers you have for meebo.com).