Back in 2006, some folks at the UK's University of Cambridge Computer Laboratory realized something: their computer science students were different. Kids from previous generations came to college with both hardware and software experience because they experimented with their computers. But by 2006, most of the new students had no programming experience. They hadn't grown up in a world where you were encouraged to take your computer apart or modify your software or hack...well, anything.
These folks decided to do something about that. So they built an inexpensive computer about the size of a credit card and named it Raspberry Pi. The Pi has many features, including video, audio, a USB port, a LAN hookup and more.
There are two models: Model A has one USB port, no network hookup and 256 megabytes of RAM, and Model B has two USB ports, Ethernet network hookup and 512 megabytes of RAM. The Pi runs various flavors of Linux from an onboard chip, and accepts SD cards.
The Model A costs $25 USD, and the Model B costs $35 USD. The price, plus the do-it-yourself community that has embraced the Pi, are what makes this little computer so interesting. For $25 you can give your kid a device that does a lot of the things your laptop or cell phone does, but you won't have to worry about them taking apart your new phone.
The Pi encourages experimentation, whether you want to use the computer as a gaming device, or to build a robot, or a garage door opener. Pi users can hook the computer to an old TV for output, and plug a keyboard into the USB slot. Judging from the number of old TVs I see at yard sales, picking one up should be very inexpensive. So with just a few items, your kid (or you) can set the Pi up and start tinkering.
Whether you call it 'hacking' (in the best sense of the word) or 'modding' or 'tinkering,' time spent learning the hardware and software in invaluable. It gives both children and adults a DIY (do it yourself) attitude, and the freedom to experiment--to learn, test, and grow.
So check out the Raspberry Pi site, and think about supporting this excellent project by buying one.
Note: I grew up fooling around with TRS-80 and later Commodore 64. What computer did you first use, and what did you do with it?
(The pic is from http://www.raspberrypi.org/faqs)