it's an oldie and rarely ever on reruns, but in the second season they had a female substitute lesbian teacher that all the boys drooled over. No one knew what a lesbian was and Cartman's mom told him lesbians like to lick carpet. So all the boys were sitting in the living room licking actual carpet. Cartman finally says "I've been licking carpet all day long and I still don't feel like a lesbian". Hands down my favorite episode.
Butters is clearly the best character on that show.