If Marty McFly had a transportation upgrade between his skateboard and his hoverboard, it might look something like this.
The Sidewinding Circular Skates consist of a pair of 10-inch rubber wheels with foot platforms. Apart from riding with a sideways stance, the gadget appears to be a futuristic take on roller skates.
Rather than pushing off the ground like a traditional skateboard or skates, the user gains momentum from a Segway-like propulsion by leaning side to side. Braking is achieved by touching one's toes to the ground.
An extendable rod can be attached to offer the rider training wheels of sort.