Ask YC: which Ajax Framework? How to deal with language diversification?

I think the question has been posed before, but I can't seem to find the thread. So which Ajax framework is everybody using?

Also, it seems Javascript is developing similarly to LISP and Scheme, in that lots of variations of the language develop, all with slightly different philosophies. I guess I just have to pick a random one and be pragmatic about it? It's hard for me to do, though...

Edit: or is the first step of a true LISPer to create his/her own version of the language?