Someone who has interest in anything with educational value, electronics, RPGs, Sci-fi (books, movies etc), sex, Anime, Music (the kind that can be well known ie: Radiohead, Voltaire, The Smashing Pumpkins, The Dandy Warhols, The Beatles etc.. or underground ie: Noise band music, Hip Hop, etc..), Taking electronic things apart and tweaking/modifying them, Video Games, May like sports, Play an instrument like guitar, drums, violin etc, watches popular shows to educational shows, has a fair amount of friends they are close to, socially well adjusted, knows how to have fun not only in a nerdy but in a cool way too.
Friend: Up for the Radiohead concert on Friday?
Cool nerd: Damn I'd love to go because I love them but I have a D&D game, I could cancel.
Cool Nerd: Oh I so will.
Person: So what do you do for fun?
Cool nerd: I hang out at clubs, go to Noise band shows, circuit bend, play D&D, watch House, Battle Star Galatica, Ghost Hunters, Paranormal State, and medical shows, listen to Aerosmith, Stereo Total, The Pumpkins, Velva, Sounds Happy, Radiohead, Harry and the Potters, and VNV Nation!
Person: Damn you are nerdy but in a cool way!!!