When I'm sleepy I press my thumb against my nose ridge to help against the insomnia present when being up late because of school (or WoW for that matter :P).
And the mental clarity is also amazing! When you can't focus on a math problem, or just can't find the answers after trying time after time, do this. It really helps you into sudden realization, though not as well as meditation. But it's 9001 and one times quicker as a meditation session!
Good luck to all you Bloggers out there!