http://www.terraria.org/

this game looks so fucking cool

its still in alpha stage so a lot of the graphics and stuff are subject to change but the core mechanics are there and it looks awesome. online 2D adventure game with tons of building and going underground to find treasure and dig holes and collect items to summon powerful monsters for better equipment.

http://www.youtube.com/watch?v=UGo7iMUcxLc - gameplay vid

http://www.youtube.com/watch?v=Udp5ozoYfxM - lets play made by the developers

aaaaaaaaa i am stoked for this