Terraria

I've actually not played this game but from what I seen it looks wicked fun. It's an indie game with old school graphics and its available on steam for $10.

From what I have gathered it's just a massive sandbox, you can build pretty much anything you want and go on endless adventures alone or with friends. Some of the monsters I've seen for this game are really awesome. But the whole game looks pretty cool.

Grab your tools and go! You can do many things in Terraria: make weapons and fight off a variety of enemies in numerous biomes, dig deep underground to find accessories, money, and other useful things, gather wood, stone, ores, and other resources to create everything you need to make the world your own and defend it. Build a house, a fort, even a castle, and people will move in to live there and perhaps even sell you different wares to assist you on your journey. But beware, there are even more challenges awaiting you... Are you up to the task?
The developers said that all updates to the game will be free as well, new items/monsters etc. It really looks like a worthwhile game.
http://www.terraria.org/

As for what I have been up to lately...well since Team Fortress 2 is now free to play I have been messing around on there. Its nothing special really but its fast paced fun and its free. I like playing Demo and bouncing grenades around corners. :)