Like Quake III Arena, but open source!
Genre: First-person Shooter
Remember Quake III Arena back in the day? It was a heck of a lot of fun, and still is, but if you're looking for something new, or just want to support the open source community, OpenArena is a must-download. Not only does it feature better graphics than Quake III, but it's less CPU-intesive in some circumstances. Huzzah!
What you'll need
OpenArena is very easy on your netbook's delicate hardware. The only relevant requirement is an OpenGL card, which all netbooks should have.
Reviews and Awards
I didn't have time to dive into reviews for OpenArena, but a simple Google search found that people really like the game. There are some complaints about the clothing of some (female) characters, which clothing is nearly nonexistent. OpenArena was the base used to create L3DGEWorld, a visualization program for network data. OA has also been used to test streaming graphics from a server in computer science studies.
If you have kids that play OpenArena, or are offended by the almost-nudity in the game, you can relax. Removing this questionable content is easy. Just open up the 'baseoa' directory in the main game folder and delete 'pak2-players-mature.pk3'. That's all it takes. In the place of the deleted characters are clones of whichever player you're using when you start a map. Know that you won't be able to join a pure server with the package file missing.