Gates open at 3 p.m. (according to their radio commercials), with warmups at 5, time trials at 6 and racing at 7. I think tickets are $30, with $5 off coupons available at Indianapolis Kroger stores (if you don't have time to stop at Kroger, sometimes you can pick up a coupon from somebody near the ticket windows).
For more information:
http://www.trackenterprises.com/