For anyone who has to deal with a "nerdish" individual, The Nerd Handbook is great reading and totally describes some key aspects of nerdish personalities. Obviously it doesn't apply 100% to any one individual, but a lot of it is surprisingly accurate. If you are close to me or another nerd, I highly recommend reading it.
On my first read, I took exception to two things in particular. The article suggested that nerds don't like to travel and that nerds don't have any interest in food. As a Computer Science major I can hardly deny nerdish leanings, but travel and food are two of my favourite things. Upon reading further though I realized that in my case I internalize both of those things as "projects." Although I enjoy them thoroughly, I'm pretty sure I enjoy them because of my desire to understand them and to "do them right." When I do things I really like to do them correctly. I often refrain from doing things because I know that I don't have time to do them properly and thus I would be unhappy doing them. At least that's how I justify my procrastination.