Following up on some earlier comments . . . I have always been interested in the correlation between nerds and music.
One of the hallmarks of nerddom is an obsession with trivia, and the music world gives you many opportunities in that regard. CT and I had a coworker in the publishing business who bought CDs by metal bands from all over the world --- especially the hokey old-school guys with the Dungeons and Dragons imagery and the leather pants.
I tend to go through different phases, but for several years, my bread and butter was "soul jazz" --- very accessible blues/R&B/gospel flavored jazz, usually with a wailing tenor sax and a screaming Hammond B3 organ. During this phase, I was playing in an R&B/oldies band and got stuck driving to gigs with a guy who was into progressive jazz fusion kind of stuff. We took turns playing CDs and generally grew to hate each other's music.
Nerds have an urge to categorize and put things into boxes, and that's certainly how I come at music. When I get into something new --- say, surf instrumentals --- I'm always trying to figure out where the music came from, what defines the genre, what it evolved into. Some music nerds takes this tendency and become purists and get very intolerant about what is allowed in a particular style, too --- bluegrass and Irish traditional music are full of these characters (although more often among the fans than the players themselves).
Me, I'm always interested in understanding the "pure" form of the music (although most music ends up being a hybrid of some earlier styles, on closer inspection), but I also want to know what happens when you add some different ingredient to the mix. An earlier poster mentioned Gaelic Storm, which is a good example --- an Irish band that uses a djembe, an African drum. To mention another pet project of mine --- a rockabilly band with a 50's R&B-style saxophonist (not a huge stretch).
Another option for the music nerd is to find a more overt combination of nerd pop culture and music. The Renaissance Faire bands, the filk singers that do songs about fantasy and sci-fi, even Led Zeppelin doing songs about the Lord of the Rings. I've thought for a long time that a surf instrumental band could borrow imagery from Silver Age comics --- Lee, Kirby, and Ditko, but also that old DC stuff like Challengers of the Unknown and Sea Devils. I helped my friends the Poprocks [www.poprocksfanclub.com] write a comic book awhile back that features the band booking a gig in Hell, too...