I used binaural beats about 10 years ago, hoping that it would help me to study. I was using audio cassettes piped through piece-of-shit headphones, so I gave up on it after a while, but it did produce a subjectively noticeable effect on my mental state. After reading the wikipedia page on it just there, I poked around in Audacity and figured out how to make my own. The visual equivalent looks interesting too, and might be worth some experimentation.