This Webisode is probably the most ridiculous thing you will ever see. I am recommending it highly.
Slant Magazine
"Childrens Hospital. If ever given the chance to go hang out on a show's set for just one day, I don't think I would hesitate in choosing Adult Swim's exuberant Childrens Hospital. In addition to the fact the series is a massive melting pot of almost every notable "indie" comedic talent working today, it simply looks like the construction of each scene is a regular cork-popping festivity (this season even featured a Party Down reunion of sorts). The series has come far from its web-based roots, capturing in only 11 minutes what other ensemble comedies fail to do in twice the time. The expertly delivered, wide-ranging jokes come in rapid-fire succession, and while it may appear as if much of it is improvised (sans the unusually well-choreographed musical numbers), Childrens Hospital devotees will realize that there's a surprising amount of continuity and overarching material at play here that, when the moment is right, surfaces to reveal one of the smartest, most conscientious comedies on TV."
IMDB'd
NSFW - Adult Themes may have some language
Episode 1