Coffee and Learning
A medical fact I don't think many people are aware of, which I've just gleaned from my (dyslexic) daughter Shelley who is studying medicine:
The caffeine in coffee (and presumably teas as well) reacts with the chemical in the brain that creates memory links, and actually chemically blocks the process of remembering!
So while you can keep yourself up all night by drinking lots of coffee in order to write an essay or complete some other assignment that doesn't have to be remembered, it's a waste of time (and lost sleep) to try and learn or revise by drinking lots of coffee to stay awake. In fact the less coffee you drink during periods of intense learning, the better. Water, little and often, is much better for the brain.