must've been that scene where Kenny falls into hell in the movie bigger, longer and uncut. Some very cool 3d effects there.
The rest is made with cheap paper pressed on eachother or something. They mention it in the episode 'Free Hat' (the one with george lucas and steven spielberg)
<a href="http://www.d2lodshop.com" target="blank">D2lodshop</a>
<a href="http://www.gatcity.com/forum/forumdisplay.php?f=3" target="blank">GAT City</a>
<a href="http://www.rhymbox.com" target="blank">XMPP instant messaging</a>