Feather racing, great game for kids

All you need is two feathers.  You drop the feathers at the same time, and cheer your feather to fall faster than your opponent's feather.  Feather race!  Feather race!  Feather race!  EYEAAAAH!

Wow... I must remember this for when I have a kid but right now this is completely irrelevant to my interests.

Or drop two sticks off a bridge and see which one gets to the other side first