From the site:
Art-o-mat machines are retired cigarette vending machines that have been converted to vend art. There are 82 active machines in various locations throughout the United States. The experience of pulling the knob alone is quite a thrill, but you also walk away with an original work of art. What an easy way to become an art collector. There are around 400 contributing artists from 10 different countries currently involved in the Art*o*mat project, and they're always searching for fresh work.