At most new car shows they're constantly trying to keep everything clean. But at the fairplex the dirt is part of the fun.
"It's the biggest off-road weekend in the United States," said expo spokesman Marty Fiolka.
Off-road race trucks will be tearing it up in front of thousands, flinging soil and showing that a few piles of dirt are no match for their 800-horsepower engines and purpose-built suspension.
Or you can watch the freestyle motocross riders really get some air. Two wheels or four, we're in the Mecca of off-roading.
"Really, the heart and soul of it is in Southern California," said Fiolka. "San Diego, Baja, out to Arizona, that whole corridor is really where the heart and soul of the industry is."
Watching is fun, but so is doing. You can strap on a helmet and boots, sign a form, and Yamaha will let you take one of its ATV's out for a spin in the dirt.
If you're into smaller scale action, you can try your hand on the remote control on one of little screamers.
Off-roading isn't just about flying through the air and making a lot of noise. Some people's idea of a good time is to have a mellow vacation.
At the expo, a jeep with a tent on the roof could become a home away from home. It's stocked with a slide-out fridge and stove.
So forget staying in a developed campground. These adventure-mobiles will climb almost every mountain to let you set up camp where your only neighbors will be birds and critters. And this is not your parents' RV.
"No its not," said car spokesman Mario Donovan. "It's a Swiss army knife on wheels."
Whether your idea of getting off the pavement means some adrenaline or peace and quiet, the world of off-roading seems to have room for everyone.