When I was young, a trampoline seemed like a really fun idea. It was right up there with the kind of pogo stick that had springs in it, or the early mopeds, whose battery could be restored through pedaling. We never had a trampoline, nor stilts with springs, but we did have a modern moped for a while. I remember that the moped was pretty cool,but I do not really remember riding it very often.
I remember riding simpler things, like a bicycle with a banana seat and butterfly handlebars. Almost everything was within a mile's drive of our house, and traffic was never bad. My hope is that as fuel becomes more precious, then the push to build bike-only trails accelerates.