Just a selection of my current favourite science T-shirts:

Schrödinger’s Cat
This is a play on the famous Schrödinger’s Cat paradox.

Glass Half …
This makes fun of physicists’ obsession for precision and accuracy. I think it’s quite a complement actually.

Quantum Dot
This pokes fun at the wavefunction collapse – the idea that a quantum mechanical system can be in more than one state until “observed”.

Snakes on an Inclined Plane
I’m not even going to explain this one. Either you get it, or you don’t!