In an early morning meeting, one of my Indian-born coworkers complained in her Mumbai accent, "It's like a game of whack-a-mole. Every time you deal with one thing, something else pops up."
Whack-a-mole has become a standard metaphor, but I wonder how many people have ever actually seen the carnival game that it derives its name from. (Unless there's a computer version that I'm not aware of which keeps it in current. Wii mole, anyone?) Certainly, I've never seen a whack-a-mole game in person, and I'm guessing that it's not very common on the west coast of India either. However I've certainly made whack-a-mole analogies myself, despite never having experienced the game myself.
Some things seem to live on almost primarily as metaphors. A number of common metaphors center around arrows and archery, yet how many people (other than those of us who got the chance long ago at Boy Scout summer camp) have actually seen an archer fire an arrow?
I wonder how long a metaphor can live on in common usage after the reality it's based on has faded into obscurity.