South Park: Season 2, Episode 11

2 - 11: Roger Ebert Should Lay Off the Fatty Foods

The kids go on a field trip to the planetarium. All of the children except Cartman are acting weird. As usual Stan and Kyle, with Kenny's sacrifice, try to get to bottom of the mystery. Meanwhile, Cartman wins an appearance on a snack commercial. The four boys get to the root of the strange planetarium.