I just watched the feature film The Lords of Dogtown and the documentary Dogtown and the Z-Boys. They both cover the 1970s skateboarding scene in Los Angeles, depicting how a bunch of school-age kids basically invented the modern sport. Like a lot of underground movements, upcycling what society had abandoned played a role in their early efforts.
In the documentary version, the Z-Boys remember making their first skateboards by cutting up old roller skates and salvaging the front panels off of dresser drawers to serve as decks.
Photojournalist Craig Stecyk documented the phenomenon, writing in 1976: “Skaters by their very nature are urban guerillas: they make everyday use of the useless artifacts of the technological burden, and employ the handiwork of the government/corporate structure in a thousand ways that the original architects could never dream of.”
The elementary schools in and around Dogtown were built to manage the challenges posed by the valleys found in the area. Concrete drainage ditches existed in all the playgrounds, and the early skaters uses these as concrete waves, applying surfing moves to riding them on four urethane wheels.
Then a record drought hit California in the 70s, so people were forced to drain their swimming pools. The Z-boys would sneak into people's backyards and skate empty pools, an activity that essentially invented bowl skating, and paved the way for vertical and aerial manoeuvres that are central to skating today.