OLD.COM :)

We did this for the Uni O worked for about 7 years ago. PCs would kick the users off at 10 past 10 at night (should have gone home 10 mins before) and re-ghost the pc's before systematically shutting them down to be woken up the next morning by the students.

All in all the whole thing worked really well and yes, it saves a LOT of money :)