Modify those cheap, low-quality headphones you get on airplanes so that they can be used at home for (almost) anything.
Step 1: What You Need
For this Instructable you will need:
Wire Cutters and Stripper (Scissors will work but it makes it a bit harder)
Electrical tape (Or just plain Scotch-Tape)
Step 2: Cut Up the Headphones
Grab your the wire and the strippers, fold the wire and half and cut in the middle, and then strip it and all the wires inside. (I mad the mistake of cutting right at the jack, which ruined it.)
Step 3: Connecting the Wires
Now you need to connect all the small wires in such a way that both speakers turn on when the end prong is plugged in. I had four colours of small wires; black, white, pink and yellow. You need to know that two of the wires from the jack will not be used.
To test which wires came from the end prong, I chose a colour, and connected them (I started with black and I connected the black wire from the speaker with the one from the jack), and tested the other wires by connecting the same colour wires together, one at a time, with the end prong plugged into the computer until a headphone came on, which it didn't. So I disconnected the blacks and connected the yellows and tested again. One of the headphones came on when yellow and white were connected, so I left them connected and cut away the two remaining wires coming from the jack.
Then I had to find out which of the two remaining wires coming from the headphones was positive and negative. I connected the black to the whites and the pink to the yellows with no results, so I switched them and the second speaker came on. I twisted the two bundles together.
In the end I had the white from the jack connected to the pink and the white from the headphones, and the yellow from the jack to the yellow and the black from the 'phones. Of course your colours may be different, but if you have Quantas headphones, you don't have to test.
Step 4: Insulation
Now you have to insulate the wires from each other, and you can use electrical tape or scotch tape. I fist tape the wires to insulate them, then taped them together, and finally taped it around the wire.
Step 5: Finished
Now you don't need to go out and buy another pair of ripoff apple headphones for your ipod when the original breaks. You could also hook up a switch to the wires that switch it between single prong and double prong for airplanes. If you stock up on free headphones each time you fly you could sell 'em to your friends for $3 each to make some quick cash.