Most effective thing I've found so far is good old ephedrine (now
always combined with guafenesin, an expectorant, which I assume is
added to make you throw up if you take too much). It is available
over the counter and speeds up your thinking like nothing else.
Of course, it increases your body odor, makes your thingy shrivel up,
and coming down from it can be a drag, but if you're in a bind, it
works like a charm. I often use it when I have to give a public
presentation and need to be sharp.
I've tried the nootropic Piracetam and there is some research that it works, but the results have been equivocal for me.
Some folks say Provigil (modafinil) works like a charm, but you need a
prescription for that. I've tried Olmifon (adrafinil) which is
the racemic mixture from which Provigil is derived, and it works
okay. It is not available in the U.S., but you can
order it semi-legally from overseas pharmacies like
biogenesis labs.
Technically, you are supposed to have a prescription for it, but if it
is interdicted, the most they are likely to do is keep it for
themselves. I received my packages opened by customs, but they
let it pass through.
Hope that helps.
Warm regards,
Hugh