Modafinil is marketed as Alertec in Canada and Provigil in the U.S.and is dispensed as treatment for severe narcolepsy. It is an amphetamine derivative and allows you to stay awake for days without loss of productivity. It also does not interfere with your sleep should you decide to count sheep. It is used by the U.S. Air Force when conducting recon missions that require pilots to be awake for days and can't stop anywhere (as it would give away their position). You can buy it from
http://www.qhi.co.uk. Good luck with it -- you're taking it at your own risk.
D.