Interlocked, by Armor Games, could be the game that most strongly speaks to my undeveloped spatial reasoning skills (an odd skill set for a geometry teacher, I know.)
However, for developing a stronger ability to visualize three-dimensional objects, I have seen no match. This game consists of figures put together in such a way that you can only move one at a time. Your job is to analyze each figure from the different views and then get the pieces apart. Sounds simple, but wait until you try it.