Breaking news! Pay attention, people of the Internet! Apple has revealed that under some circumstances, iPod and iPhone users may receive a mild electrical shock to their ears through their earbuds. Knowledge base article TS2729 has the full technical details about how something called “static electricity” can build up in your precious iPod or iPhone and then lay in wait until you insert the earbuds into your soft, vulnerable ears.
Apple tries to deflect the attention away from themselves by stating “Note: This condition is not limited to Apple hardware and static can potentially build up on almost any hardware and could be discharged using any brand of earbuds.” How many other manufacturers have a knowledge base article about this, huh? That's what I thought!
This reminds me of the problem with some models of Sony Vaio laptops:
you have connected your PC (laptop) to external power, you have disabled your phone line, (while) simultaneously being connected to a grounded peripheral, and you are touching a metal part of the PC, and your phone rings
I can't tell you how many times I found myself satisfying all those conditions. Thank goodness I wasn't using a Sony Vaio at the time!