Simpsons is a trusty favorite.
Old episodes of SNL and Kids in the Hall will make me laugh til I pee.
Reno 911
Arrested Development
The Office, both British and American.
Spongebob, though Ive seen the eps so many times I think its losing its magic. Need new episodes!!!
And my new favorite is King of the Hill. Holy shit that show is funny.

Family Guy is a little too slow for me. Ive tried and tried to get into that show, but I just dont like it when jokes are overexplained to me, especially not very good jokes. Stewie's kewl tho.