Pinning this up so that keshwyn can find it later.

If you liked Myst, Creatures, or any of the other exploration/world building games, you will love Waking Mars. It punches all the exploration, puzzle solving, and discovery buttons. Flat-out awesome.

http://www.wakingmars.com/

Unfortunately, it is only available for iDevices at the moment. I still recommend it highly -- not enough to suggest you go buy a device just for this purpose, but if you have one, get the game, and play it. The experience is tremendous. I have not enjoyed a game this much since Uru.