About two or three years ago, it snowed a lot, and since the gritters (The people who drive around sprinkling grit on the roads to de-ice them, not sure if you have them over the pond or in Aus) don't go down my road, because it's steep enough that the gritters won't go down it easily, but not steep enough for it to be a danger, meaning they have to for H&S reasons, it had been very snowy, then the snow was compacted by the cars going down the hill (No-one could get up) it meant that there was very, very little friction.
I bet you're wondering when someone got hurt aren't you.
My friend had an old skateboard, and had taken the axels (Axles? My speeling of some werds is treibble)[sub]Yes that was a joke, a terrible one at that[/sub]
Anyway, they took them off and put some wax on the bottom side. His idea was that you take a running start, and jump onto the board and slide down the road, he knew it would work because "He'd seen his cousin do it"
Though you might not expect it to, I was wrong and it worked perfectly, it was just the balance of the person after the jump that was a problem, which we had nailed after an hour. This meant that we got bored and built a little ramp out of snow, and packed it hard so it would take our weight, we soon managed to get pretty good at that, with a few falls every now and then.
Then, as a friend who I'd invited that lived a road away had a go, and was pretty good. Then on his second go, he tried the jump, and landed it, if a bit shakily, as he slid further down the road and then the first friend, who barely knew the guy, came running out from some random persons drive and rugby tackled the unlucky guy!
Friend 1 sprained an ankle
Friend 2 broke an arm and a rib.
All I could do was laugh.
EDIT: tl:dr version, friend was sliding on a skateboard on snow, a frined tackled him and broke his arm and wrist.