GeekGal, judging by your name I assume you have thought of this, but in case you haven't: Have you visited ThinkGeek? www.thinkgeek.com.

If your dad is a computer geek, there is an absolute myriad of cool and nifty geek toys, as well as geek t-shirts, geek computer components, geek clocks, etc. If you have never been there, I encourage you to check it out.