Humble Bundle is easy to explain. You buy games and pay as much as you want (from 1$ ) , and you decide where the money goes. It can fund charity, developer or tip Humble Bundle guys. Simple?
Most of the offers on http://www.humblebundle.com are for Mac, Windows and Linux. They also include soundtracks.
So, take a break and engage in some cool Indie gaming supporting charity and linux at the same time. Genius!