If you're 22 and you have excess money (meaning your tax advantageous retirement contributions are maxed, your bills are all paid for, and you have 6-8 months of emergency fund), and you don't want to start your own company (and you don't want to donate the money), then you can become a small angel and help others start their companies. The reason I'm not saying things like "buy CDs", or "put it in a mutual fund", is because you're 22, this is Hacker News, and you can afford to swing for the fences and play conservatively later (eg. when you have a family that depends on you).

Also, by keeping the money in the bank, you're in effect saying that the rate the bank is giving you is the best return you'll get for your money (voting with your dollars). At present time, this is most definitely not the case, so it may be beneficial to look into anything that produces a higher return than bank rates (currently maxed at ~1.5%/yr).

In my experience, starting a company early yields extreme results beyond just money, and you're in a position to do so -- why, may I ask, do you say "besides starting a company"?

EDIT: Not sure why I'm being downvoted. Parent poster was looking for advice on how to invest in himself with excess cash. I'm posting from experience since I've been there, and looking to hopefully get him on some track to put his cash in a place that generates higher returns than in the bank. It's silly to give the bank free use of his cash with the return they're giving him, when he could be using the same one to generate higher returns elsewhere.