I stumbled across a great online T-shirt shop, courtesy of a mention in Pharyngula. It’s called the Retropolis Transit Authority, and has lots of cool retro-future oriented stuff (think steampunk, and you’re halfway there). Here’s one of their nifty advertising banners (no, I don’t get paid for this…), linked to their site:
So if you’re looking for a fun shirt, say as a gift (for yourself or somebody else), check it out! And if you’re in the mood for a poster or coffee mug instead, wander on over to the artist’s site for that kind of goodness.