South Park - Season 2 Episode 1
Terrance and Phillip in Not Without My Anus

The show starts off with the build up from last seasons cliffhanger revolving around Cartmans paternal origins. However, just as it seems they are about to get on with the second half of "Cartmans Mom Is A Dirty Slut," they do a 180 degree turn-around and reveal that for April Fools Day they will be showing Terrance & Phillip in "Not Without My Anus".