The God's Country Fat Tire Festival is this weekend at the Lawrence River Trails. Yes I know this is not a gravel event, but many riders use their cross/gravel rigs to participate. See picture below from last years God's Country Marathon event.
Festival includes an off-road duathlon on Saturday (long, short and relay classes) with a traditional cross country event on Sunday. Sunday's event has a class for everyone including the 3 hour Marathon class and a fat tire (3.8 inch tires) only event. We have live bands each day and free food.