Don’t know if any of you know about this, but there’s aparently been a community effort brewing in YouTube for some time aimed at bringing South Park episodes online. Frankly, I don’t know whether the company allows this or (more likely) whether this use is technically illegal, but I haven’t been able to find as extensive a collection for any other show.
In any case, if you’re a South Park fan (I’m not, generally) you can now get your fix via YouTube.
Edit: The videos have been taken down due to copyright restrictions. Guess they were illegal. Sorry about that.