Step 1: Materials and Tools.
Step 2: What to Do (part the First)
Cut four strips of card. The exact dimensions are not critical. My strips ended up as almost two feet long, because that was the size of the card I had, and about two inches wide because I had a two-inch wide piece of timber that I could use as a ruler.
One end of the card will be the handle, so round it off. The other end won't be the handle, but you can still round off one corner.
Step 3: Make It (part the Second)
Again, dimensions are not critical (look at the photos to get an idea), but I left a curve of card at the far end of the chucker to give a "flick" to the cracker's flight.
Glue the layers together. I used hot-glue because it was quick, adds an element of strength to the structure, and I had already switched the thing on when I walked into the shed. Make sure that the cracker runs smoothly down the slot.
When the layers are firmly stuck, trim the ends for neatness' sake.
Step 4: Use It
The style you use is up to you - over-hand, sideways - but remember, folks, even a cheesy snack can cause pain at high speed.