In Summer 2009 I participated in the NSF-funded SURF-IT (Summer Undergraduate Research Fellowship in Information Technology) at the University of California, Santa Cruz. This REU (Research Experience for Undergraduates) involved creating an iPhone/iPod Touch application called Teenvity that is designed to motivate teenagers to exercise by playing games that require movement. The application is molded to the user’s personality; the system selects an agent, motivational phrases, and games to suggest to the user based on a short personality test.