One of the most controversial animated series in history, South Park's 'low budget' looking animation in no way takes away from the program's ability to cut to the heart of current social, political, and cultural trends has meant it has managed to stay relevant long after its crude humour might otherwise have worn thin.
Spawning a movie and a recent (very good) video game, South Park continues to push buttons and boundaries each year as its collection of foul-mouthed, precocious young Colorado boys tackle everything from racism, homophobia, political correctness, and Barbara Streisand.
While many other comedies have 'sold out' and become generic, repetitive jokes in recent years (I'm looking at Family Guy and one of our top two), South Park continues to produce witty satire. It might be less common these days to see a truly great episode, but it remains one of the best at what it does.