Phoenix Wright

Well, I'm not sure if you regard caffeine as a drug, but thats a pretty good place to start. If you don't want to consume anything, just place yourself in an environment that's difficult to fall asleep in, such as in a cold room, to prevent yourself from considering sleep as an option. And of course, keep yourself preoccupied at all times.

Keep busy, splash cold water in your face, take a cool/cold short shower, do something physically active for a bit (but not over-exerting), and possibly drink caffeine.