There's a drug that's supposed to keep you awake. hehehe.. I got a whole bunch of them, but no, they are not for sale. Yes, it is legal. You should be able to find it.
Something tells me that crossing international borders with this would cause more problems than it would solve.
You can get it legally in the US with a prescription if you work shift work or that sort of thing. Frequent travel and jet lag probably counts too.