You probably by now know about the blog Stuff White People Like, which talks about stuff white people like.
By "white people", the blog doesn't mean all white people, but rather white urban twenty- and thirty-somethings with money to burn.
Stuff white people like (according to the blog) that I'd guess a lot of mathematicians also like include coffee (if you don't know why, you're probably not a mathematician), "Gifted" children (lots of mathematicians probably were), Apple products (mostly judging from what sort of computer colloquium and seminar speakers are running, although this could be skewed by the fact that Apple users, being in the minority, are probably more likely to bring their own machine), not arts degrees (arts degrees apparently make people more interesting to talk to at parties, a concept entirely foreign to us), graduate school (although it seems to be humanities PhD programs that they're referring to), and bad memories of high school.
There are also a lot of less-good imitations: Stuff Educated Black People Like, Stuff Lesbians Like, Stuff Gay Guys Like, Stuff College People Like, Stuff Asian People Like, Stuff White Trash People Like, Stuff Unimaginative Bloggers Like, and perhaps others.
But what about "Stuff Mathematicians Like"? I know that I wouldn't do a good job with it -- but someone should. I'll get you started -- the set of stuff mathematicians like includes coffee, Rubik's Cubes, saying things are trivial, being proud of the uselessness of one's work, and the prefix "co-". (So what is "ffee"? Okay, there's another thing mathematicians like -- bad jokes.) Feel free to name other elements of this set.