Here is the article I mentioned in class. It's two years old. Extra Credit points to whoever can find updated information on the situation. I'm pretty interested and haven't found anything yet.
Here are links to the orbital simulations that we looked at in class, in case you want to mess around with them some more:
Also: We didn't get around to chatting about it in class, because I wanted you to have some time to get together with your groups, but don't forget to consider the implications of non standard orbits, axises, and rotations. Consider Uranus, so tilted as to be pretty much perpendicular to it's revolutionary orbit. Consider the distance of your world from it's star, and how long it takes to orbit said star. What implications do the orbital lengths/axis tilts have on seasons, and what implications do those, in turn, have to life on your world? Life would be quite different on a planet that went through a winter period that lasted an entire generation's life span!
A fantastic article over at gamasutra discusses stories in sandbox games. It thoroughly discusses the various scenarios in which story can play into these games, and how to best incorporate it there. Game students, read this article.
It also mentions one of the best (free) indie games you've never played.