Prop comics of Politics: Republicans:
This tire gauge ploy from them, it's prop comedy, just like the purple heart band-aid. Both just props to extend some ridicule.
This takes me into some territory I've been thinking about and may actually suss sometime: Republican humor (Limbaugh, O'Rourke, and McCain) is almost totally mere ridicule. It's only funny if you already buy into the joke -- if you believe the ridiculed object is worthy of ridicule (Think about ridiculing some people, institutions, or deities who aren't considered worthy of ridicule--fill in the blank).
All humor includes ridicule, but I'm thinking one reason there aren't more standard-issue comedy shows featuring right-wingers is that ridicule wears thin. The Daily Show uses derision a lot, but it derides a broad swath of media life (including, especially recently, Obama), and it features all sorts of staples of humor beyond ridicule.
I'll think about this some more.
In the meantime, I'll insert Doug and Dinsdale Piranha below.