Programing the brain to sleep at will?

Hey, I was just curious, is it possible to "program" your brain to fall asleep at will? Sorta like this:

Me: Gosh, 30 min till bus gets here, and nothing to do.
Me Thinking: "Fall asleep NOW!"
Next Thing You Know: "Zzzzz"

I know people say not to get to much sleep, so you would have to be careful with this. But I find it would be extremely usefull for various things, such as falling asleep easier, something to do when waiting, quick nap, etc.

If anyone has any answers and techniques, that would be great. What I think would be REALLY cool is just programing your brain to go directly to REM, but I dnow how healthy that would be.:P

That would be pretty cool to be able to do, but I just don't think it's possible. I mean, you figure if it was you would have heard of it by now. There are people who can, apparently, slow their heart rate down to a couple beats per minute and even THAT takes time to do. Shutting your brain down would definitely be harder, in my opinion.

Only thing that might be possible is through meditation - if you can somehow speed up the process between the time you begin to meditate, and reach the point of theta or delta waves. But going from beta to theta/delta in zero seconds.... not likely.