What are these two making now!?!?

I LOVE my boys but they can do some things sometimes that makes me stop and say "what are these two making now???"  I thought you might like to play along this time. 

They need safety googles if that helps, probably not though.

Here is some of the supplies that they used.  Lots of wood and some files, drill, and a saw.

They spent time sawing at the wood (Dad was always right next to them for safety)

Sam even got to use the power drill, only with his dads help though. (mostly so mom did not have a heart attack)

Finishing up at the end.  Filing and screwing. 

Oh there is an elastic, any guesses yet.  No?

Sam assembling the end of his.

Surprise they built their very own catapults!  They love them so much.  After all you need a good sturdy catapult when you want to attack a castle.

Don't you think it is huge, that is our car next to the wheel.  LOL  These were actually kits that we got at Wal-mart.  It is from the company Red tool box.  They have lots of other projects on their site if you want to check it out.