Students from the University of Wisconsin-Stout won the 2011 National Rube Goldberg Machine championship. The theme this year was to water a plant, which the students accomplished in 135 steps.
Although not the contest winner, a team from Purdue University smashed the previous world record by constructing a Rube Goldberg machine with 244 steps. They watered their plant by way of recreating the history of life on Earth.
You can see another perspective of the Purdue entry with some explanation here.
By the way, the 2012 task will be to inflate a balloon.