The term "hang up" (to terminate a phone call) probably comes from a time when telephone receivers literally hung from a bracket, like this.

A lot of phrases come from the time of sailing ships, such as "to know the ropes," "three sheets to the wind," etc. I've got a booklet-dictionary somewhere that lists dozens of these, but I wouldn't know where to find it now.

"A flash in the pan" is a mishap involving a flintlock pistol or musket.