This has to be the simplest Instructable ever. While some people may think this easy creation is stupid, I think it provides fun for younger children.
Step 1: Step One
Find a long piece of cardboard ( At least 17.5'' long and 3'' wide). Then cut it so it is 17.5"x3". Tada! A boring looking piece of cardboard! Now, throwing the cardboard.
Step 2: Making the Cardboard Fly!!!!!!!
Okay, it's time to throw! Hold the cardboard like in the picture. Throw the cardboard angling a bit up. The cardboard will spin around in the air and act like a boomerang, flying back to you! Enjoy!