What invention would you take back to the year 1000 to amaze the people of that time?

Question

It doesn't necessarily have to be see something which would change their world, it could simply be something that you think would be cool to take back and show them. However, it has to be something practical- for example, it can't need to run on electricity, as you wouldn't be able to plug it in, or something that would run on batteries, as these would run out and you couldn't buy any more! I'd be really interested to see what people come up with! :-)

Answer 1

CYCLE :)

Answer 2

Damned near anything you'd take back would get you burned as a witch, or heritic.  

Answer 3

AIDS.

Answer 4

  How about a portable radio with a cd player and a solar charger?

Answer 5

The yo-yo or the frisbee.

Answer 6

I can't decide either Mad-Cow Disease or mercury tainted fish.

Answer 7

The atom bomb...Id like to see what they do with that!