A circular track may be flat or hilly. Riding on the track is a big wheel sized larger than a rider compartment. The rider compartment is supported out bound from the big wheel's axle. The big wheel's inbound axle is attached to a radius arm which is powered by a conventional rotating hub. The radius arms are pivotally connected to the hub to allow an up and down movement on a hilly track. The rider compartment has a magnetic coupler assembly to the axle to enable an automatic and/or a rider controlled head over heels spinning of the rider compartment while the big wheel is traveling in its circular path around the hub.