String theory and its big brother M-theory blew my mind when I first learned about it. I was particularly attracted by the idea that it might take 11 dimensions to provide a unified "theory of everything". As a hobbyist in computer graphics, I spent a lot of time in university trying to imagine what it might be like to visualize higher dimensions by taking various 3D slices of hypercubes & the like and trying to animate them on the computer. Fun times, and a lot more interesting than the business software I write for a living these days!

Who's the author of Discipline? I might have to look it up, always interested in finding new reading material. And have you read Flatland? I think that was the start of my fascination with abstract geometrical spaces.