On so many levels I am so tempted to try this, but I just can't bring myself to - but I am in constant envy of co-workers who 'juice' and watch their productivity soar.
/r/nootropics has a lot of useful information in their wiki [1] and the community is pretty friendly and helpful to newcomers.
See for example: http://en.wikipedia.org/wiki/Juiced:_Wild_Times,_Rampant_%27...