Strollers manufacturers are constantly trying to outdo one another, and this one is no exception.
The Quinny Longboard Stroller allows adults to skateboard with their baby riding sidecar in an attached stroller seat. Safety is somewhat controversial, however, since it is only approved in Europe and not in the U.S. The strollers are available for European buyers for a purchase price of 599 Euros (nearly $650 at this writing).
My advice: if you want to exercise, get a jogging stroller. You have more control over the baby’s safety. When your child is ready to skateboard, teach her so you can ride alongside each other, instead of using your baby as a bumper!