From a story on CNN we learn that one in 5 respondants to a survey reported that they take brain enhancing drugs.
There's a drug solution for everything, isn't there? A better brain builder is good sleep, adequate water intake, a variety of excercises, and thinking activities like crossowrd puzzles and reading! This takes some effort compared to popping some pills, but you will be buidling new neural pathways that provide natural drugs the brain produces. This will enhance your performance for the long term. Drugs provide temporary results but then wear away. In the course of time higher doses are needed to provide the same results. Soon you're addicted and what will you do then? Not to mention all kinds of awful side effects including a weakening of the system you took the drug for in the first place. The brain will be dependant upon the drug since you effectively shut down it's natural production of dopamine and other critical neurotransmitters.