We were hunting dragons one day and.. wait, this is not the beginning of this story. The beginning of this story was way boring - it all started in the local DIY shop, where TO obtained 6 1-meter dowels, and cut 5 of them in half. Because that's what you would need to make a catapult. Plus some yarn and elastic band - is that simple.
Join four dowels to form a square.
Then, repeat with another 3 dowels.
Now put the two structures together, attaching two more dowels. Depending on how far you want your catapult to shoot, you can change the height where you join.
Now add your last 1/2-meter dowel a little lower from the top. Attach your un-cut dowel as shown:
Hot-glue any plastic container you have around to the top of the long dowel.
And you are ready to hunt dragons. Attack! :)