Here is a link to something called the Fatigue Avoidance Scheduling Tool-FAST.
It is a computer program that displays the relation between sleep, or lack thereof, and performance. It is meant to help schedule activities when those activities occur at odd hours or for long durations. The Air Force uses it I believe. It is quite illuminating to plug in the numbers and see how low the level of performance is after not getting enough sleep. I think it quite good.

http://novasci.ms11.net/