Rhymes with Orange consistently makes jokes that are meant to be clever, but they rarely are. The joke here is that skunks are black and white. Of course a skunk has no need for a passport, so the premise is absurd. Absurdity can be funny (as Stephan Pastis proves well), but it's hard to cross absurdity with reality and not lose something.
Runners-up: Baldo, Blondie, Brevity, Curtis, Family Circus, Garfield, Hagar the Horrible, Mother Goose and Grimm, Red and Rover
Lio is probably the best example of how absurdity can be funny. Of course everything in Lio is absurd, which helps make it work. We do not get distracted by the fact that Death is hitching a ride because it's Lio, and we're used to anything happening.
Runners-up: Dilbert, Get Fuzzy, Pearls Before Swine, Watch Your Head