Stumbled across
this link and thought it was very interesting.
Here is my favorite quote:
... In contrast, according to the latest Top 500 list, the most powerful supercomputer in the world, Roadrunner at the US governments Los Alamos nuclear weapons research laboratory, produces just 1.46 petaflops. In fact, the total output of Folding@home is greater than the combined output of the top 6 fastest supercomputers on the list. ...