Many years back someone built a ramp out of an empty 205l oil drum and some plywood sheets, ended up with 3 or 4 people layed side by side on the other end as people jumped over them!.
You never see kids nowadays building jumps, might have a go at one on Sunday with my lad.
We used to do that, I always made sure I was the one nearest the ramp, just in case they didn't make it. we also used to set up a race track around the housing estate, some of the track took in part of the building site, it became a bit mad at times, we all thought that we were Barry Sheene.
I know its not the done thing these days but, we didn't have helmets, body armour or knee and elbow pads, I'm sure that we were lucky not to end up with a serious head injury or broken bones, maybe us kids were a little tougher back then, nobody told us that we couldn't do these mad stunts and nobody seemed to care, its just what boys did, perhaps they still do but they take it to the skate/BMX park.
Its quite interesting really, a friend of mine has just bought his son one of these American Stunt bikes, tiny little things with a steel frame and chunky tyres, it has ape hanger bars and doesn't have any brakes, kids are supposed to stop the bike by stamping on the back wheel, its a heavy little thing but it looks like fun. I have no idea what these bikes are called but a second hand one cost my mate £300, he should have bought a Tomahawk....lol