This article describes the development, field testing, and evaluation of an interactive computer program, "Life Challenge," developed by the New York State Department of Health as a tool for enhancing adolescents' sense of self-efficacy in HIV/AIDS prevention programs. The computer kiosks were field tested in 13 sites serving high-risk adolescents. The program uses a time travel adventure game format to provide information and nonthreatening skill practice. Users record and play back their responses as they "negotiate" with their chosen partners. A proof of concept evaluation with analysis of 211 audio responses found that users took negotiating tasks seriously; statistically significant learning gains were achieved on knowledge items and in self-efficacy scores (greatest improvement for those with low baseline self-efficacy levels). Challenges and problems encountered in implementing the project are described, and the potential of using computers for skill practice and educational interventions in health education is explored.