OnLive are still very much a-live despite this week's bizarre bankruptcy/buyout/employee equity grab, and to celebrate, you can get four indie games free on the service for the rest of the weekend. If you've never tried Defense Grid or Dear Esther, now might be the time to do so.
To participate, go here,select the game you want to get a full play pass for and then register it to your account. You'll have to repeat the process four times to get all four games. More details on the OnLive blog and Facebook page.