ROFL - not quite! Those are actually amazingly simple to make. I didn't have any sort of plan, I made the design up myself, but that's more of a testament to how ridiculously simple they are to make than any sort of design prowess on my part.
If you have ever seen an M-80, it's a cylinder shaped fire cracker with a loose fuze sticking out of the side. A model rocket igniter, is little more than a match head with 2 wires sticking out of it. Pull the fuze, insert the igniter, tape down, and any 9v DC current will result in an instantaneous M-80 BANG!
A note if you plan on actually DOING this -- do not connect the battery until everything is in place -- AFTER the whole thing is taped up, AFTER the fishing line is attached, AFTER both ends are secured to trees, and AFTER the piece of cardboard is firmly breaking the circuit.
It helps to actually use a 9 volt battery snap on connector which you can get real cheap and re-use. You do NOT want the M-80 going off while building this thing, and CERTAINLY not while you are holding it. M-80's are a bit powerful, and can damage your hand!
So build the whole thing attaching the wires to the 9 volt battery snap on connecter, put everything including trip wire in place, and the last thing you do before leaving it is to snap the connector onto the battery.