Back in the days when kids made a lot of their toys, some devious little mind came up with a way to fire rubber bands off more than their own thumbs. Thus was born the rubber band gun. Today, they're enjoying such a resurgence of popularity, that you can even buy guns carved from wood, that replicate actual weapons such as repeating rifles, pistols and more.
But for a simply weapon to give your friends a snapping good time, try this. Gather up a piece of wood, such as a short section of 1x2" lumber, a wooden clothespin, some Crazy Glue, a nail and a hammer.
You're going to want to glue the clothespin at the rear of the 1" side, which should be on top. But first, take a nail no more than 2" long, and 1/8" thick, and cut the flat head off, and file it down. Mark on the piece of wood, where the end of the clothespin will be, and drive the nail into the wood, sharp end down, about 1/3" from where the mark is. Leave about 3/4" of the nail sticking up.
Now drill a hole through the end of the clothespin, with a bit that is slightly larger than the width of the nail. Make sure you drill through both sides of the pin. Apply glue to one narrow side of the clothespin, from the open end, down to the drilled hole. Don't get glue in the hole. Now place the clothespin on the piece of 1x2", making sure it's got the nail fitted through the hole. You might want to try the fit, before applying the glue.
Cut a notch in the end of your wood, just below the top, so you can hook one end of the rubber band there. Now pull it back, and hook the other end over the protruding nail. To fire, just open the clothespin. There should be enough motion to allow the upper part of the pin, to push the rubber band off.
For more zing to your gun, cut a second shorter piece of wood and glue it underneath at a 90-degree angle, to approximate the shape of a pistol. Insert your nail and glue your clothespin to the back of the "grip". This will make for a longer stretch to the band, and more snap when you fire.