One thing you can do to really help people learn about computers is give them something to see and touch. I would not let someone touch a plugged in computer, but you can make a working mock-up of one for safe handling. Though the basic parts may change, the same parts are there in all systems. You still have to have a cpu, memory, storage via drives and add-in or daughter boards. Here is one such mock up we made.
Since it is a working computer, I plan to encase it in a clear plastic shell with air vents. Then we can use a quick loading live os such as Tinycore linux to demonstrate what the system can do. With Tinycore linux you do not need a whopping machine to run it. Most any newer x86 based machine should work fine. The system in the picture is a pentium II with 64 megs of ram connected only to a cdrom drive and a floppy. Tinycore will work just fine on such a system by loading from the cdrom. Do not need a hard drive for it unless you want to. Good way to make use of older equipment without purchasing newer systems. You certainly not run Apple OS/X or Microsoft Windows 7 on it, but who needs them. You can easily connect to a web server or the internet to run any applications you need. Anyway I will probably use this and other units to help talk about hardware as we go along.
That leads me to another low power distro called Zencafe linux where you can use it to set up your internet cafe with low powered server and clients. Zencafe does require a bit more horsepower than tinycore linux, but it is still so low that you probably could get the systems free if you looked around. What a way to make money with old computers that are just lying around. Of course you will have to have and internet connection to take advantage of it, if nothing else it will be a good way to set up a simple computer lab for say a child care center, a school, church, or other non-profit entity inexpensively. Might even be something to set up if you have a large family and or lots of relatives that like to visit if you can not afford a boatload of computing equipment.
Anyway, I hope these two ideas can help you out in some way. I am still working on the honeypot project as I have time and plan to continue it soon. Till next time….