I have a regular, full-time job as an architect. In my free-time I train for endurance athletic events, such as triathlons and marathons. I've been thinking about spending a few weeks in the United States to compete in some events there. The races all pay prize money, which ranges from $20 or $30 up to more than a $1,000. I've heard different things about visa requirements. Can I use a tourist visa for these races?