South Park

The fact it happens literally at the beginning of the episode, and everyone's in silenced shock for a few seconds cause they can't comprehend what just happened before they utter he's dead is what makes it funny for me.

Bonus points that he held in his farts for the girlfriend he met doing that song for the rainforest group the episode previous, and SHE ended up reviving him and bringing him back to life. One of the few early episodes he was alive at the end, just to kill him off at the beginning of the next one.