Frankly I'm amazed there isn't already a thread about this.
I just picked this game back up yesterday after going more than a few years without touching. I have forgotten how much fun it is.
If you don't know what it is, basically you pick a location to start a zoo, a starting amount of cash, and then start building. But you have to work to increase your zoo fame and funds to get the rarer animals and more advanced facilities. You have to keep your guests and animals happy, so that you not only get profit from admissions fees but donations as well. The ways to get more money are fairly flexible, from the aforementioned donations to altering prices of admissions and concessions to manipulate guest's spending. You can get periodic challenges in challenge mode, have unrestricted building in free play mode, or go for specific victory goals in scenario mode.
The last is what I dived right back into the moment I finished going over the tutorials; and a tough scenario to boot. I've got to make a five-star zoo with only endangered animals in the exhibits. Amazingly, I'm doing better with it than any other scenario zoo I've done before. That's not saying much though, since I'm constantly under $5,000 in funds, and I keep getting told that my board of directors bought an endangered animal without telling me. Still having a blast with it, though; already at three stars, and the fame from releasing animals to the wild is maxed out. To top it off, I'll soon have enough money saved up to get a black rhinoceros; I'm sure that'll get more guests interested in my zoo.
So this seemed like the sort of game people who like dwarf fortress would like, and I thought it would be cool to talk about and see who else plays it.