Aaron Koblin uses micro-payments to crowdsource his art projects. Here's a description of one of his projects (an interactive version of the above image is here):
Ten Thousand Cents is a digital artwork that creates a representation of a $100 bill. Using a custom drawing tool, thousands of individuals working in isolation from one another painted a tiny part of the bill without knowledge of the overall task. Workers were paid one cent each via Amazon's Mechanical Turk distributed labor tool. The total labor cost to create the bill, the artwork being created, and the reproductions available for purchase are all $100. The work is presented as an interactive/video piece with all 10,000 parts being drawn simultaneously. The project explores the circumstances we live in, a new and uncharted combination of digital labor markets, "crowdsourcing," "virtual economies," and digital reproduction.
Another of his projects asked participants to sing a song, piece by piece:
Bicycle Built for Two Thousand from Aaron on Vimeo.
More on this project and more audio tracks here. His newest project asks participants to draw a frame from a Johnny Cash video to be included in an ever-changing animation. Participate and watch the video here. Artist's website here.
(Hat tip: Flowing Data)