I don't know why, but today I got to semi-remembering the clothespin gun that I and a few of my friends played with when we were kids.  I can't remember how to construct it, so I Googled it.  I found Clothespin Match Gun.

A useful site, to be sure.  However, the ones we made didn't require a rubber band, and certainly didn't require as much modification.  Also the leftover piece was not discarded, it was used to cock the gun.  So I guess I'll have to keep looking.

We only fired big gooey spitballs with ours.  If my dad had caught me shooting flaming matches, he'd have tanned my hide.

Oh yeah, my dad showed me how to make one in the first place.  But it's been a while, he probably doesn't remember how either.