If you're a nerd, you have the basic ability to like hip hop, and have always dreamed of blasting songs about the X-Men in the hood with your windows down, then Adam WarRock is the answer to your prayers. I don't think the dude has any actual albums, but he has a million mixtapes and singles that you can download for free from his website.
He covers everything from comic books, to video games, to nerd shows like Dr. Who. I think he might have some songs about non-geek stuff but who ****ing gives a ****?
http://www.adamwarrock.com/
Any nerds who ain't tryin' to hear can eat ****.