I'm doing a woods haunt this year and I think I want to do a variety of scenes....something i really want to do is the slingshot apparatus...they sell for like $4,000. An actor jumps and is slingshotted in front of the group walking the path and then he is pulled back onto the platform. IS there anyway I could make this...like attach something to two trees and swing through them. Where could i find bungee cords? Any ideas would be helpful!