Olivier's photo reminded me of this one from my collection: not quite a tshirt, but some pretty good schwag if you ask me... It's an American Chemical Society Li mug!
The ACS sends a mug to each member on his or her anniversary displaying the element with the atomic number corresponding to the member's anniversary year. You get a Lithium mug for 3 years of membership. How nerdy and totally cool at the same time is that, huh!?!
... View more