Well, I was not born a nerd… but I soon became one. 
So here’s what I consider to be the stuff that made/makes me geek or a nerd
1. Took Calculus in high school… in my junior year
2. My favorite author in high school was Arthur C. Clarke
3. I spent countless hours playing RPG games on my hard-earned NES
4. My Verbal SAT score was almost half of my Math SAT score 
5. I observed how calculus was applied in real life
6. I loved to derive equations and formulae
7. I memorized a car’s performance and features
8. I could tell what car was on the road after a quick glance
9. Star Trek: The Next Generation is da bomb
10. Capt. Jean-Luc Picard is da man. “Engage”. “Make it so, Number One.”
11. I love sci-fi and fantasy movies
12. Was a fan of Lord of the Rings before the trilogy movies came out.
13. Went to Polytechnic Institute for college. ’nuff said
14. I was a bookworm when I turned nine. All I did was read.
15. My GPA from college … was high. We’ll leave it at that.
16. My major was aerospace engineering.
17. I catch up on latest technology developments
18. Gizmodo.com : Need I say more?
19. My hobby is building and tweaking computers.
20. I like to fix computers
21. I help moderate four computer/technology forums
22. I play loads of games, mainly on PC
23. “Final Fantasy VII” is a masterpiece
24. “Baldur’s Gate I & II” are masterpieces
25. I play GRAW (Ghost Recon: Advanced Warrior) online almost daily
26. I thrive on cool gadgets
27. Yet I’m very weary of technological advancements
28. I can compress DVD into a smaller compressed video files
29. I know “pi” to 11th place.
30. My job is a rocket science.
Is that sufficient to be categorized as a nerd/geek? I believe that geeks are mostly pretty benign and safe people. Nerds however can be somewhat stuck up. Geeks are the ones that make the world go around. Understanding people that are different from you is part of what makes you a human. Fearing difference is the beginning of violence among humans. Trying to understand that difference and embracing is what love is.
I also loved calculus and took it in h.s. and also took the AP exam for it. I would be the only one in class that would work out the extra credit problems that took a page or 2 to solve. I loved derivatives, etc. I My second favorite math was geometry; I liked theoroms and postulates. I play Sims (does that count as RPG?). I like Star Wars but can’t get into Star Trek nor LotR. I also love to read (duh) and collected stamps and Baby-Sitters’ Club books when I was young. Other than that, I was pretty cool.
Oooh… forgot to add that I collected stamps for a while in high school.
Also took AP exam for Calc as well… Just admit it, you are a geek!