Using Google Maps or Earth, create a racetrack using local roads and share it with everyone. It can be a circuit or an A-to-B rally stage. You can trace it out with a paint program like I've done here.

This is Cape Cod Community College, about 2 miles from my house. The 1.1 mile ring road is a pretty nice drive but you could also make diversions into all the parking lots or use them as pits.