Piracetam is a drug in the class of drugs known as
Nootropics. Nootropics are defined as substances which can boost human cognitive abilities. Piracetam can improve both short and long term memory recall without serious side effect, and can do so safely. Drug safety measured by the LD-50, which is the dose at which 50% of the test population dies. They use mice to test on (can't get human volunteers for this) and then scale upwards for humans using known conversions relating to things like the difference in body mass. Piracetam is thought to be very safe because they couldn't actually measure the LD-50 due to the fact none of the mice would die.
Piracetam has been used to help children with dislexia as well as people with senial dementia. In the latter example it doesn't actually prevent the dementia, rather the mental benefits mask the decline for a while providing the sufferer with another year or so before the decline sets in properly.
Piracetam will not get you high.
Piracetam is legal and cheap to get hold of via the internet (look on google - i'm not giving you sources) as the patents have run out.
Piracetam doesn't work for everyone and takes a couple of weeks to start working (a bit like antidepressants) but does work for the majority of people that try it.
It won't make you a genius but it can offer a small but significant mental improvement that can make a real difference.
There are many other nootropics apart from piracetam, but piracetam has the longest history (and thus is least likely to give you cancer in 20 years time due to some unknown factor), is the cheapest, and works very well compared to most. Personally i find it about as useful as caffeine when i'm at work.
One other thing - Piracetam is known to be 'neuro protective' which means that it actually reduces the chance of you suffering from brain damage. If you were to starve your brain of oxygen for some reason (perhaps due to altitude or drowning then being resucitated) piracetam would actually reduce the chances of damage which is kind of reassuring.
Until someone invents cybernetic brain implants (fingers crossed it happens in my lifetime) nootropics are the only way to actually fundamentally increase the functional capacity of the human brain.