If you wear headphones for an extended amount of time, chances are you'll start to feel some discomfort around your ears. This quick hack from the folks at WonderHowTo is a great way to make your headphones more comfortable for extended wear.
All you need to do is cut a length of backer rod — the thin foam tubing used before caulking — and use it to line the inside of your headphones as padding. Audiophiles should note that even a small, unobtrusive change like this can alter how your headphones sound, so your mileage may vary. However, if you've got a pair of cheaper headphones you just want to make more comfortable, this is probably worth a shot.