There are many people these days that use formatting to further their writing, but a particular example that I enjoyed immensely was Danielewski's House of Leaves.[0]
I remember fondly the experience of reading a passage with either a chase or a fall, and each page having less words (down to 1 word per page, several times), the effect of which was that you started to page the book faster and faster, giving your reading a wonderful sense of acceleration.