I have gone on before about why It's Always Sunny In Philadelphia is one of the best shows on TV that you're not watching. The characters go to the sort of lows other more prominent shows can only dream of. To give you a flavour just read some of these episode titles - Charlie Got Molested, Charlie Wants an Abortion, The Gang Goes Jihad, Mac Bangs Dennis' Mom. Bare in mind this doesn't go into the fantasy world that South Park sometime inhabits. This is all stuff that could plausibly happen.
At the climax (LOL) of the fourth season the creators choose to follow in the footsteps of That 70s Show and Buffy with a completely ridiculous musical episode. I don't want to ruin it for you but any TV show that can get away with a line of dialogue like 'I think the rape scene went really well' is OK in my book. Check it out, you won't regret it... Probably.