Quite recently I came across information & videos about a new game being developed called Terraria. Not too much information is available as of yet, but what has been shown off so far is fairly promising. There are a number of good YouTube videos already, which includes a LP series showing off the game in its Alpha state. Definitely something worth checking out
You can find the official site here: http://www.terraria.org
Here is a nice fan-run forum that has sprung up: http://terrariaonline.com
Here is the official YouTube channel for the project so far: http://www.youtube.com/user/demilogic
And below is a trailer. Enjoy!