Jonathan Coulton

Jonathan Coulton is a renowned geek and musician. He once did a project that he called Thing a Week. During Thing a Week, he wrote one song per week for an entire year. Some of the songs turned out really well, but during weeks when he couldn't come up with anything the songs can be just plain nonsensical. As a result, Coulton did not know his songs very well and sometimes forgot his lyrics mid-set. I think the fact that he managed to do this shows how skilled he is.

Coulton's Website: http://www.jonathancoulton.com/
Coulton's Biography: http://www.last.fm/music/Jonathan+Coulton/+wiki