Thousands of spectators and participants will be converging on Twentynine Palms today and tomorrow for the 43rd annual Hilltoppers off-road motorcycle Grand Prix. The grand prix is an AMA-sanctioned event and part of the GPR Big Six Grand Prix Series. The gates open 6 a.m. Saturday and Sunday; the races start at 7:30 a.m. today and tomorrow. Motorcycle riders of all ages and abilities will race on desert courses that include jumps and dips. There will be food, vendors, and fun for all ages. The event will be held at the Twentynine Palms Motorsports Arena, about 3 miles east of the city off Highway 62. Tickets are $20 per day, with discounts for military and children. For more information visit www.hilltoppersmc.com.