AD & D Book of Sex.
Carlton Draught Big Ad. A beer ad worth watching. Rather meta.
Hetracil! The spoof anti-gay drug! (For men only.)

PMS: the Game! (Potentially offensive.)
Lost as done by assorted different directors. Probably more amusing if you're a) familiar with Lost, and b) familiar with the other directors.
Birdhouse in your Soul music video via Google Video Search.
Penis cake. No, seriously. Penis cake. (Warning: explicit detailed pierced trimmed-haired erect frosting penis.)