The best part of the Cartman Aids one was the jokes about are you sure?, are you HIV Positive? haha so half assed I know but i remember those jokes from school. And it was funny cause Cartman just couldent get over it and the scene lasted for a long time.
I watched the old Iceman one from Season 2, cracking episode. Its the one where they dig someone up who is from 1996. And it is now 1999. They wonder if he speaks English and if he can socialise with the would around him. The bit about how s*** the internet was the was funny.