ManBearPig seems to be a weak reference to global warming, an issue Al Gore wants to bring to America's attention. The episode has Al Gore making up a monster called ManBearPig, convincing no one that it is real, and claiming victory over it after flooding the cave with water from a nearby river.
Kyle knows how to swat away the basketball. Probably something he kept from his days as a basketball player (with Mr. Garrison's knees).
Boy, is Al Gore ever petulent here. He also has delusions of grandeur which lead to a superhero complex.
Cave of the Winds, Manitou, Colorado.
"Maybe I'll make a movie. A movie starring me." - Al Gore does indeed have a movie coming out this summer called An Inconvenient Truth, about global warming and our denial of it.
The stalactites and stalagmites:
The Hanging Mushroom
Man With Helmet And Two Bowling Balls
The Two Sisters