I design logos for Bitcoins.
Designing a graphic identity can take me weeks, but this particular project is for me an experiment. The logos I design are quickly made: it takes usually 1 to 2 hour per logo. They are totally adapted to the (really) small brief I receive by mail, from total strangers. My clients usually want something smart, quickly. The small economy of those projects are for me interesting and inspiring design constraints. I use only open source fonts. Sometimes, I draw the typeface myself when I feel inspired.
Total income this year: about 5 Bitcoins http://ecogex.com/logos/