Have you ever come across a situation where in you have to have an important online discussion with some one and you are running out of a microphone but you still have a headset (earphones)? Here is a trick by Robin Good where in you can convert your good old spare headset into a live working mike by just plugging in your headset into the microphone jack of your computer. I've tried it myself and it really works, although the sound quality is not as good as a real microphone as told by Robin. But who really cares as long as you are able to get your job done with this workaround in an emergency situation.

Tech-Recipes has detailed step by step instructions to use your iPod headphones as a microphone.

Sometime back I had accidentally plugged in a microphone into the headphone/speaker jack and guess what? Yeah, it worked like a speaker!