Amazon Mechanical Turk is a web marketplace that basically lets you buy labor for tasks particularly suited for humans (i.e. easy for man, but hard for computers).
The Sheep Market is a neat, albeit a little whimsical, application of this concept. For a 2006 art project, Aaron Koblin, then of the Department of Design|Media at UCLA, "bought" 10,000 drawings of a sheep facing to the left from thousands of workers for $0.02 each. The work and the animation process are captured and then displayed as an artwork!
Average time spent drawing each sheep: 105 seconds
Average wage: $0.69/hour
Rejected sheep: 662
Collection Period: 40 days
Collection rate: about 11 sheep/hour
Unique IP addresses: 7599