the "Not Without My Anus" episode was probably the funniest South Park episode ever (right after the "Spontaneous Combustion" episode).
They don't show it on t.v. anymore, though, you have to go to some site to actually watch the episode. (and read what the episode is about, because it was an April Fool's joke against viewers watching South Park. So you have to read somewhere what the episode is about, because it's a really funny episode.)
South Park, Charmed, Buffy The Vampire Slayer / Angel, Tru Calling, Family Guy, TrippingTheRift, FreeForAll, Futurama, Jackass, Lost, That 70's Show, Celebrity Deathmatch