My buddy Eric and I play a lot of Left 4 Dead together. So when he wanted to give me a gift recently (I do feed him lots of

pizza), he hit upon the perfect thing: a Left 4 Dead T-shirt that only fans of the killer zombie-hunting video game would recognize. It simply shows one of the health-preserving pill bottles that dot the game's world on the front. On the back, it says, "Pills here!" -- which the characters yell out whenever they come across the bottles. That's it. If someone who recognizes the design and expression sees it, you share a geek moment. If not, you get a quizzical stare.

I have another shirt like that, given to me by my family. It says "Umbrella Corp." with the fictional company's logo. When I was wearing it recently at Trader Joe's, a worker passed by me. "Resident Evil!" he said quietly, using the same tone as in that video game's opening voice-over. We both laughed and then went about our business.

These shirts are usually created by fans using custom shirt sites such

as Cafe Press and Zazzle. Their designs cleverly avoid copyright infringement, but they also offer a great way for fans to get in touch with their inner geek. They're not just for video games, either. There are, for example, ones for Weyland/Yutani (the corporation in the Alien films) and "09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0" (the processing key that unlocks DRM-protected content on HD DVDs).

Do you have a shirt that expresses your inner geek? If not, looking through Zazzle or Cafe Press, which would you get?