X-COM: UFO Defense and Sequels for $5

X-COM: UFO Defense and its four sequels are getting the discount treatment on Steam this weekend, where you can pick up all five titles for only $4.99. As you probably already know, these sci-fi classics are more about turn-based strategy than role-playing, but the earlier titles have enough RPG elements in them to warrant a play-through or two. And for $5, you can't go wrong.