I have a bad habit of staying out until I'm too tired to drive home. Then when I do drive home, I have to find a way to stay awake. I usually crank the AC to the max and turn the radio up really loud. In the classroom though? Read the student newspaper. Not much learning actually takes place though, so it might be better to just stay home and sleep and try to get more sleep next go round so you're not tired during class.
Or, you know, coffee.