Revolution Raceway is an RC vehicle track in Appleton. They host competitions, but they also have open practice hours when anyone can go and give it a try. They also have vehicles for rent. The practice hours seem to be most afternoons and evenings, but I would call ahead or check online to verify.
122 S Memorial Drive ~ Appleton, WI ~ (920) 955-2121
Admission: $7.50/vehicle, $2/rental