I rerun cat 6 cables in the entirety of my house at night because i couldn't sleep. Something i'd never had the will to do in the morning. Never understimate the productivity pulses you get at night. That is if you don't have to wake up early that day :P.
Absolutely - the best time to get that urge is in moments when you're not in a position to really take any action. You fall asleep with the happy glow of prospective progress, and by the time you wake up you've forgotten about having to do anything.