Peaked youth in the '70s. That means enginieering Evel Kneivel-esque ramps from cinderblocks and left over plywood, for jumping bikes in the alley. After awhile you learn to build them to the side, so the garbage trucks can still pass by. Love it when you're first getting started on jumping from ramps, then the guys on the garbage truck stop and the guy on the back hops off, comes over, and says "Mira...you need to put a couple of blocks in here to support the middle of the ramp, like this," as he's stuffing a couple of bricks under the weak unsupported part of the board. Pointing at the kid who's turn it is to jump, then to the ramp, "Now go!", the jumper's altitude and distance greatly increased over previous jumps, shocked kids' faces all around, as all the garbage men get a belly laugh and are on their way...