If you are looking for a new show that is witty, yet as offensive as South Park, I highly recommend “It’s Always Sunny in Philadelphia.”
Start with Season 2 or 3 (the first one is okay, but is missing a chemically-imbalanced Danny DeVito).
Unlike Lost or Heroes, the stories don’t really build on one another in any meaningful way… kind of like Seinfeld. The writers basically find a hot topic to parody (like abortion or gun ownership) and look at it in the most absurd angles, making fun of everyone in the process.
Here is a small clip, though you can grab them all with Bit Torrent (… unfortunately they don’t sell copies here in Korea):