Step #1: The most important of all the steps. BUY THE KIT. This makes things much easier.
Step #2: Explain to the kids you do not put it in your mouth - ever. Who knows what horrible disease this stuff causes.
Step #3: Pick your colors and fill the mold with some magic bouncy ball powder.
Step #4: Dip the mold in water for 1 minute.
Step #5: Take the mold off, and behold - a bouncy ball!
Step #6: Pose for your parents with your newly made toys.
Step #7: Make it a science project. Explain that the 8 balls they made are like the 8 planets, and how in the olden days there used to be one extra planet named Pluto but that was light years ago...
Length of time the balls will continue to bounce: approximately 2 days. They get hard as rocks and hurt like the dickens when you step on them.