Ahh, yes. We did this too in junior high and high school.

We called it "Ice Blocking." No one quite knew what we meant by it, which was to our advantage.

Hint:
Watch out for dirt. Before you know it, you will be laying face-down in wet grass wondering what the hell just happened, while your friends laugh so hard that they fall off their blocks as well.

Hint #2:
Adidas shelltoes or some other slick-bottom shoe is preferrable for ultimate speed and control.

Have fun.