Lately I have finally gotten around to installing a game I bought last December in the Humble Indie Bundle 4.
Night Sky is a beautiful game in look and sound. It has a very relaxing, ambient feel similar to Osmos, though obviously the gameplay is completely different.
In Night Sky you control a sphere through physics intensive platforming challenges. Your ability to control the sphere changes from level to level. Mostly you'll use the arrow keys to bounce off of various obstacles and jump ramps, but sometimes even this will be taken from you and only gravity will propel you. You will also slow down for precise control, control pinball paddles, speed up to make long jumps, and reverse gravity. You also power various apparatuses with your motion.
I've not beaten it yet, but the content I have seen has been very satisfying and I can't wait to dive back into the beautiful dreams of Night Sky.