I enjoyed bits and pieces of the episode. The opening murder sequence was great, and while Butters' shock was hilarious, the real gold there was Clyde's complete and utter indifference as he simply continued his schoolwork. The clip from Dances With Smurfs was great too, though it might have helped that I was having a discussion with a friend about Avatar not fifteen minutes before the episode aired where that exact title came up.
Overall, though, it was a weak effort. I've been trying for some time now to pinpoint what it is that has made my affection for the show's new output wane, and while it was hard for me to put it into words (it's more of a general feeling than anything specific), I think I have it:
South Park has always been influenced by popular culture, but how Parker and Stone have gone about implementing what's in the news or currently popular has changed dramatically. In its best days, South Park could take these issues/themes and use them in a way that served the story organically, moving the episode along.
For an example, take "Timmy 2000." There they took an episode that's overall theme was acceptance and managed to pepper it with jabs at the overdiagnosis of ADD and the readiness of parents/doctors to put kids on drugs.
These past seasons however, have seen the show simply making the "story of the week" the plot in itself and attempting to fashion some sort of storyline around it.
I think the best way to put it was that South Park used to be about taking our culture and twisting it into this bizarre cartoon universe, often poking fun through exaggeration and their own interpretation. Now, they simply throw the actual issue in as is and let its own outlandishness stand. And for me, it's simply less fun.
Of course, it's best I end my rant by saying that I find the greatest episodes of South Park will always be the random episodes that have nothing to do with anything. Give me Chili-Con-Carnivals and panhandling Loch-Ness Monsters anyday.