Broke and bored? Try these games!
SHOOTERS
Xonotichttp://www.xonotic.org/Free, multi-platform open-source FPS, with classic "arena" style gameplay reminiscent of quake and unreal tournament.
PlatformWindows | Mac | Linux
Brick-Forcehttps://www.brick-force.com/ The REAL Counter-Strike for kids. They say it's part minecraft, part FPS, but it's more like Blockland in respect that building and fighting are too different things. You can build your own maps to play on, and in some game-modes, build and fight at the same time! The actual gameplay is a bit like Counter-Strike. You should try it, it's fun!
APB: ReloadedAll Points Bulletin: Reloaded is a third-person shooter set in the crime-ridden city of San Paro, where Enforcers, legalized vigilantes, face off with Criminals daily. Customize EVERYTHING, upload or create music themes, design your car, make your own symbol. No two people in this game are the same.
PlatformWindows
SIMULATION/STRATEGY
LinCity[On ubuntu software center, couldn't find a good link]
LinCity, which stands for "Linux City", is a free-open source sim-city alternative for linux users.
PlatformLinux
Warzone 2100
http://wz2100.net/Warzone 2100 is a open-source RTS game set in a futuristic world. Originially published commercially in 1999, it was released as an open-source project in 2004 and is still supported today!
PlatformWindows
RACING
Project Powderhttp://projectpowder.outspark.com/In a future where Earth lacks snow, scientist have created wormholes to travel to other planets with winter-like environments for a chance for everyone to experience the once-legendary winter sports. These new planets with less gravitational pull raise the bar for new riders and new tricks. Race, battle, or collect coins in 3 different game modes.
PlatformWindows
Other Games
Toribashhttp://www.toribash.com/Toribash is almost a whole new genre of games. In Toribash, you have to kill your opponent, but rather than it being real-time and having limited move sets, in Toribash you simply control a rag doll with large number of joints moveable in any way you chose in a turn-based strategy game. An impressive game.
PlatformWindows | Mac
I'll add more soon! Suggest FREE, preferably open-source games to me.
Mobile games count too, but only really good ones. If I receive enough suggestions I'll add it