I came across this t-shirt site a few months ago called Threadless, not only do they have some very cool T-shirt designs but they are all user created.
The idea is that you design a T-shirt, upload the design and if it gets lots of votes then its gets printed! Better yet if you design gets chosen for printing then you get $2000 cash and $500 of vouchers.
So since it is a bit rainy today, I created my first t-shirt design and submitted it.
_[Updated]: alas my design got bounced back as needing some tweaking so it is now in critique mode. Check it out and let me know what you think: http://www.threadless.com/critique/34044/Hello_waveform_