I'm not a huge nerd but I am proud of what I am nerdy about.
1) I can name the band and rock song you play for me between like 1960 and 2000 easily. Plus I probably know most of their lyrics and can sing the guitar parts to
2) I know almost everything possible about the following shows: Scrubs, Family Guy, Futurama, The Simpsons up until a few years ago, South Park from watching hours and hours of audio commentary several times over. I once went on a scrubs binge where all I would watch is scrubs DVDs but I only had the first 5 at the time. But I spent about 3 months straight watching it and nothing else. I think I had to have cycled through them at least 7 or 8 times. I did the same with Family Guy and Futurama just not as much.
3) I know everything there is to know about the Wu-Tang Clan and know the lyrics to all 70+ songs of there's by heart.
4) This isn't much anymore but for a while a few year ago I would study and research somewhat random things way too much...examples astronomy, 9/11 junk, pyramid history, 2012 theories, global warming, UFOs and alien, life or past life on Mars. Just nerdy stuff.