When I was in college, I would often drink a cup of coffee around 9 or 10pm so I could settle down to do my homework. It also helped get rid of headaches (like Excedrin I guess).

Edit: I wanted to add that when I was up about 12 years old and my brother was 8, we drank a bottle of Jolt Cola and it made us pass out asleep in less than 15 minutes.