Take a look at this instructable to find out how to make a Recycled Catapult.
First cut out the top of a big bottle. It should look like this.
Cut 8 lines making a +. Each cut should look like this.
Put the rubber bands, each side should look like this.
Do the same thing, put the next rubber band perpendicular to the one you just put. It should look like this.
You can skip this step if you want. Staple in the middle of each rubber band.
To make your fingers safe, tape the edges of the bottle.
Cut out a long piece of string and tie it to all of the rubber bands.
Get a piece of paper, and make it into a ball. With the same string you used for the bottle, wrap the string around the ball.
Once you wrap the entire paper ball, glue the end of the string to the ball.
Test your product! Have fun!