Strange Adventures in Infinite Space / PC and Mac – Free
Strange Adventures in Infinite Space / PC and Mac (77 at Metacritic) is a small, fun little game where you “explore the galaxy … in 20 minutes or less!”
It plays a lot like a board game — and was originally distributed by a great traditional game publisher, Cheapass Games — but it’s punctuated with arcade action, and the setup changes from play to play.

Cheapass had this to say about it:
It’s got all the fun and excitement of a traditional exploration game, boiled down to the best twenty minutes.
Your strange adventure begins on the planet Hope, where you’ve been charged with the task of exploring the galaxy and returning with as much neat stuff as possible in just ten years. Unless you find a great star drive, that’s usually not enough time to reach every star! You’ll plan your route carefully, trade with friendly aliens when you can, and try not to get blown to dust by the miscellaneous bad guys you will inevitably encounter.
Gizmondo called it “the ultimate pickup game.” GameSpy said it’s charming, and summed it up with, “While it’s about as edifying and substantial as potato chips, it’s also just as engaging and tasty.”
Strange Adventures in Infinite Space is a free download. (As is its source code.)
If you enjoy Strange Adventures, there’s a sequel, Weird Worlds: Return to Infinite Space.