Out of all the minecraft clones, this is the best one i've seen. If you can't afford minecraft, this is a great alternative. I really wish it had graphics option though. I'm running off a GT520, so the game doesn't run crazy well.
You can install your own selection of mods from an in-game catalogue or look them up and download them manually. You can install mineclone2, which brings it very close to a minecraft experience. Don't install the game from here unless you made sure it's the latest version. You can find the latest version on minetest.net/downloads
ahhh.. great but can you add invert y-axis because i'm not accustomed with the default. and add mouse sensitivity. please
Don't waste your time on Minecraft. Get this instead - Minecraft isn't much better, but with the Mods you can make Minetest FAR better than Minecraft. Be prepared to wrestle your children away from the Computer.
Of course you can add ppa:minetestdevs/stable to your repository list for a new stable viersion. If you want daily build use ppa:minetestdevs/daily-builds