In addition to being able to determine your own price, you are also able to determine who receives the money that you pay. You can choose to have the money go directly to the developers, directly to two charities (Child's Play and the EFF), or split the money between the organizations in a customizable fashion.
The sale was originally offered from May 4th to May 11th, and during that time, they were able to raise over a million dollars from the sales of the games. Of that money, $354,446 was allocated to the Electronic Frontier Foundation and Child's Play Charities.
As a way to say thank you to the participants of this sale, they have decided to allow additional sales of the bundle until May 15th, and have decided to make Gish, Penumbra, Lugaru, and Aquaria open source, and they have also decided to offer an additional game (Samorost 2) to purchasers of the bundle.
You still have some time, people, get buying!