If bitcoin is to gain any popularity in the future, at some point some T-shirts will be designed to help promote the concept.
I'm condidering making some of them myself, but it's bit early I think.
Anyway, here are some ideas of what could be written on those T-shirts :
This T-shirt was bought for 1000\\
Block number : 90000\\
and still counting...
After the barbarous relic,\\
here comes the cyperpunk money :