I reviewed Race the Sun a while ago - a fun, twitchy single-player racer that is highly addictive.
For those who don't like crashing into things all the time, they just introduced a new "sunrise" mode, where you can fly around to your hearts content, enjoying the surreal landscape. The add-on is $1.99. You can read about it here, if you're interested.
I may have to give it a go. I loved the base game, and relaxing games are a nice way to unwind after a busy and/or stressful day at work.