Check out fellow voxel game Ace of Spades[1], Windows and works great on Linux with WINE. It's a FPS with beta 0.54 out this week. Really fun and interesting maps. You build just like in Minecraft, but also fight for to find and return opposing team's intel to your base (basically CTF). Customizable maps, sniper-rifle scopes and more. Also, it's free.

[1] http://ace-spades.com/