This article seeks to advance theory pertaining to serious sport tourism, through the application of serious leisure and ego-involvement theory and the analysis of a survey of participants in the TransRockies Challenge mountain-bike event. Participants were questioned postevent about their motives, involvement in their sport, event-related travel, and destination and event preferences. Analysis revealed that most respondents were highly involved in competitive mountain biking, and were primarily motivated by self development through meeting a challenge. Many respondents also participated in a portfolio of other competitive sport events that provided similar personal rewards. Results suggest that many serious sport tourists develop travel careers centered on competitive events. A hypothetical framework for assessing six dimensions of event travel career trajectories is developed, leading to consideration of practical management implications and research needs.