I've seen this done before, but it's explained really well here - a styrofoam cooler, cheap fan and two dryer vents:
How to charge an iPod using Gatorade and an onion:
Back in 1988, as part of an ad campaign to be printed in Time magazine, Volkswagen approached a number of notable thinkers and asked them to write a letter to the future—some words of advice to those living in 2088, to be precise. Many agreed, including novelist Kurt Vonnegut; his letter can be read below.Ladies & Gentlemen of A.D. 2088:
- Reduce and stabilize your population.
- Stop poisoning the air, the water, and the topsoil.
- Stop preparing for war and start dealing with your real problems.
- Teach your kids, and yourselves, too, while you're at it, how to inhabit a small planet without helping to kill it.
- Stop thinking science can fix anything if you give it a trillion dollars.
- Stop thinking your grandchildren will be OK no matter how wasteful or destructive you may be, since they can go to a nice new planet on a spaceship. That is really mean, and stupid.
- And so on. Or else.