Do conservatives and liberals have different senses of humor? Amanda Balzer points me to a telling article by Glenn Wilson called "Ideology and Humor Preferences" (gated), published in 1990 in the International Political Science Review, in which the author finds important differences in the appreciation of types of jokes by ideology. Important graph:
I wouldn't be surprised to find that many of these differences have changed over the past two decades. Wilson suggests in the text that younger liberals were becoming less tolerant of crude sexual jokes, while I'm thinking that younger conservatives have embraced them more.
I should mention that Amanda pointed this research out to me during a Twitter discussion about whether Victoria Jackson and Dennis Miller have become less funny over the years or whether they just seem less funny to me as our respective ideologies diverge. This could make for some great research designs.