As big kids (13-16) we used to use the following weapons of choice.
We had a really steep hotmix hill that was on the mine site. We would get our mates to push us as fast as they could then see how many fishtails and 360's we could do before we stacked and took a heap of bark off.
We also used to tie them onto bikes and tow each other around smashing into gutters, this was done with skateboards too. LOL

We had flat plastic not rubber wheels on our kart.