It probably happens to me at least once a month. I'll be traveling with or working next to a friend (or my wife) and one of us will want to watch a movie or listen to some tunes. We usually end up awkwardly close to each otherone with the left ear bud, one with the rightknowing that the slightest movement will rip the headphones out.
Sure, I could get a cheap jack splitter, but that requires that we both have a set of headphones and that I keep up with a small piece of equipment.
Instead, I might spring for a set of BudBuds, which piggyback another set of earbuds onto the original pair. Normally, the subsidiary pair are simply snapped into the back of the main set, but you can pop them off whenever you want and let whomever you want listen in. They'll be ready in a couple months, for about $25.