Ace of Spades is a free beta game that Call of Duty-style multiplayer shooting with Minecraft visuals and features. Currently in beta at version 0.60, despite missing a proper game interface, Ace of Spades is a surprisingly playable PC game.
To play quickly, simply download and install the game, then go to the Ace of Spades/play page, choose a server and the game should launch. You can only change your user name by opening the game’s folder (click Windows Start button, then All Programs, then Ace of Spades), opening the Configuration file, then replacing the word ‘DEUCE‘ with your chosen word and saving. There are a ton of other hints, tips and importantly controls at the Ace of Spades Wiki.
Environments vary, from randomly spawned worlds, to ones designed by players. All can be mined and built on during battle, which makes for some interesting ideas. The map I played above was two bases separated by an enormous plateau, that had tunnels and chasms carved through it, with fighting taking place all over the place. It’s really compelling and I highly recommend it. You’ll be hard pushed to find something this good for free!