From Habr:
Divanikus: Under the noise of servers it is quite normal to sleep. I broke into the server a couple of times :) The main problem is usually a fairly low temperature.
MaxxL: The sleeping bag! Compactly folded, cleaned, if necessary we get and make a wonderful break!
FFire: Especially if you sleep under the false floor, nobody will notice.
matiouchkine: Real professionals are sleeping on a fake push.