Here are some things I found for all you Supernatural fans:
Just for funsies... Team Derp
Staying on the slaying binge, here are a few Buffy the Vampire Slayer shirts followed by a slew of Joss Whedon ones (since I'm in love with him):
So there are some of the nerdy shirts I found for this batch. I've got even more coming up soon with The Princess Bride, Big Bang Theory and other things. Make sure to stick around for those!
Let me know which ones you love!