In the thrilling conclusion to South Park's recent three-part super hero themed saga (in which we finally get some incite into why it is Kenny can die every episode but come back alive like nothing happened the next) Cartman once again lampoons LeBron James' now infamous Nike commercial in which he asks "What Should I Do?"
South Park's website did not single out the clip for us to be able to embed it, but you can watch the full episode here. The LeBron gag starts at about the 3:13 mark. Update: It's on YouTube, for now anyways.
It also makes a short reappearance in this clip before the show uses an even older meme for a joke -- the double rainbow.