MasaMania writes (with tons of photos) about street racing in Tokyo. Hashiriya is the name of the races. Seeing the photos I never could have imagined that there could be so much powerful cars in just one place.

And the rules are:

... Hashiriya never be scare of police. They memorise exactly where speed traps are setted. and they have special divice to detect police car approching. and of course, they are too speedy to be catched by police. They are also professional of not to be arrested by police.

Via GVO