Moose's rule of thumb: If I'm tired and know the boys won't put the cat in the microwave (again), I sleep.

Set the alarm for a 1 hour or so nap.
Because sometimes the provigil just ain't enough.

And trying to stick to a routine with sleep schedules helps as well.
Go to bed the same time each night, try to get up same time in the mornig.

And suzy... that icon with the ball still cracks me and my sons up. That usually helps with a boost of energy.
But that's just me...