Putting someone in the boot (trunk) of your car after a severe beating, then dumping them somewhere far away, presumably after another sound beating. The unknown aspect of being driven away in a boot adds to the psychological distress. Has also resulted in death in some cases.
In New Zealand, when someone has wronged you in a serious enough manner, this is often seen as the ultimate punishment.
A drinking endurance game involving the challenge of drinking beers whilst being fully enclosed in a car boot. Man points are awarded for time of stay in boot and amount of beers. The hardcore bootrider will encourage a course involving bends, known accident blackspots and speedbumps.
Yo man, I played some bootrider the other day and it was siccckkk, no literally it was sick, Randy is going to need to clean that out.