Some of them spent Friday at the Marathon Expo at the Cox Business Center. Seventy vendors are showing off running gear and health and fitness products. The expo is free and open to the public and runs until eight tonight and 10 a.m.-6 p.m. on Saturday.

Organizers said even if you're not running Sunday, come cheer on those who are.

"It makes a big deal to them when you're out there cheering for them as they run the race,” Williams Route 66 Marathon's Chris Lieberman said. “It helps them get to the finish line, it makes it a better experience, and believe me, they talk about it online. And they'll tell people what a great city we have."

The course is already proving to be an obstacle course for drivers.

Tonight at 9 p.m. and 10 p.m., we'll take a look at economic impact of the race.