These are some of the cool places that are out there.

Basic4GL: A BASIC programming language with built in support for OpenGL, designed to make it easy to get into OpenGL development quickly, without dealing with all the hassle of initializing it. It's a Windows only program, but it runs pretty well in Linux under Wine.

Dwarf Fortress: A game where you can design and build a fortress, train your dwarves for battle, and slay beasts. Lots of freedom for constructing traps involving pressure points, levers, magma, rocks, arrows, etc. The gui seems a bit archaic, but it's really quite fun. The developer also maintains a development blog.

Puppy Linux: Small (~70-100 MB) Linux distro well suited for use as LiveCD, from USB, and from HD. Does not require a Linux partition, so it can coexist with Windows or nearly any other OS.

Vendetta Online: Skill based space fighter online game. It's not free, but it is Very Fun. PVP is a very significant aspect of the game, and if you are not careful you will be pirated. Probably even if you are careful. But ships are cheap, so buy a new one an pop the pirate. It's named "Vendetta" for a reason. They have versions for Linux, Windows, and Mac.

Wolfire: Indi game dev company, currently working on Overgrowth, the sequel to Lugaru. They maintain a development blog, updated daily. Highly recommended.