I'm playing Dwarf Fortress now... I first started playing when VB told me about it, but the huge amount of characters and symbols (and blinking ones, either waiting for construction or two objects in the same square) make me dizzy. So I gave up.
I tried it again recently, at first I was playing adventure mode (being a NetHack player). I found the world rather empty, and it lags once in a while. Then I tried the fortress mode again - and same dizziness from the symbols and blinking. But this time I stumbled upon Mayday's graphics mod... and that allows me to really get addicted.
After many "crash dummy" clans, I'm now playing for real, in my first late summer. Farm is up and running in mid-spring, food and drinks are abundant. No magma on the met, but I have big broadleaf forests. Just started smelting and smithing, but so far very little to work on other than the gold nuggets I've found.