I originally saw this on Dick Eastman's Online Genealogy Newsletter (See the posting here.)
You know how you get better sound if you cup your hand around the speaker on your iPhone, iPod, or iPad? Well, this company in Los Angeles has developed a paper horn that you can attach to your iPhone that basically does the same thing, amplifying the sound without the need for any additional electricity or batteries. You also no longer need to hold your device in an awkward position to get the desired increase in volume.
The "eco-amp" is constructed from recycled post-consumer fiber papers and comes in 24 different designs. It costs USD$10. It can be used with the iPhone 4, the iPhone 4S and the iPhone 5. You get two eco-amps with each order. For more information, this is their web site: http://www.eco-made.com/