Scooby Dooby Doo Where Are You?

I went to open the blinds this morning and saw this:

See that skateboard at the top of the stairs there? Well, I've never seen it before. But it isn't unusual for Drew to buy things for the kids without telling me, so I asked him about it. But he denies any knowledge of said broken bone machine. Which isn't necessarily a guarantee that he didn't buy it, but upon closer inspection, I noted that it was a well used skateboard. As you know, Drew doesn't get into the whole secondhand shopping thing, so I do believe him on this one count.

So, I ask you--where did it come from? Yes, it is common for the neighborhood school-aged kids to leave bikes, scooters and skateboards in our front yard by the bus stop, but this one is in the back yard. As you can see, our back yard is fenced and the steps are on the opposite side of the yard from the bus stop. So again, I ask--where did it come from? If you can solve the mystery, you'll have yourself a Scooby Snack courtesy of one grateful Mellon.