The actual game flOw (http://en.wikipedia.org/wiki/Flow_(video_game)) came out of this research. The use of Mihaly Csikszentmihalyi's theories of flow have been part of game design for a long time, and most of the stuff in the thesis is basically common sense with a few interesting thinking points.

Some other great literature on games that also discuss flow can be found in Jesse Schell's book (http://www.amazon.com/Art-Game-Design-book-lenses/dp/0123694...) or in Steve Swink's book (http://www.amazon.com/Game-Feel-Designers-Sensation-Kaufmann...).

(edit: no coffee yet)