http://www.nicalis.com/ - NightSky: This is a great little platformer pretty much ideal for passing short periods of time with well segmented, short levels, some fun puzzles, especially now I'm replaying on higher difficulties and a really chilled out atmosphere.
http://www.youtube.com/watch?v=sf06P-_1lkU&feature=related - Vvvvvv: Again a great platformer, great music, love the level design... The inversion mechanic breaks my brain at times though much much harder than the video makes it seem lol...
http://www.roburky.co.uk/?p=13 - Reset: tiny game I found, love the song it's played to and the game itself is great for playing around with for 5 minutes, I generally aim to take as little damage as possible in the time given, my record is 67

http://www.rockpapershotgun.com/2011/01/31/a-little-help-here-tiny-barbarian/ - Tiny barbarian: Saw it on RPS, it's good fun I'm retty terrible at it though

http://www.frozensynapse.com/ - Frozen Synapse: Turn based, multiplayer, tactical, awesome.
So anyway what do other people play?