Bruce Yeany teaches physical science to 8th graders in Annville, PA and he is very enthusiastic about it. On his popular Homemade Science YouTube channel, Yeany highlights all sorts of physics experiments and demonstrations without using any special equipment. In one of his latest videos, he shares a bunch of marble tracks that he's built to demonstrate motion and momentum.
The "identical track race" starting at 1:43 might blow your noodle a little bit unless you're familiar with Galileo's pendulum research. (via digg)