Have you noticed that while a lot of people know how to USE computers these days, not a lot of people understand how they actually work? The people who used the first PCs were tinkerers, because they had to be - the computers were really, really basic and didn't automate much for you (remember when you had to know how to make it load the operating system?).
Eben Upton, one of this year's Technology Review TR35 (top innovators under 35), aims to change that with the Raspberry Pi. It's a Linux-based, programmable, tinkerable, hackable computer, designed to engage kids and turn them into the next generation of computer engineers and scientists, not just users. And it's $25.