I came across a book mentioned at Wired News called Apple I Replica Creation: Back to the Garage. The book contains detailed information on basic electronics, documents the construction of the Replica I, built by Briel Computers, and provides an understanding of the very foundation of computer operation. What is the Replica I?

As mentioned on Briel Computers:

I purchased the kit rather than the completed board. The kit comes with everything you need, but all in pieces that need to be soldered together. It took me roughly 1.5 to 2 hours to solder the components together. Briel Computers has done a great job labeling everything for you... it is quite simple to put together. Soldering the sockets, however, take FOREVER. My soldering skills increased 10 fold that day. I also added the Serial I/O card to the order, which I highly recommend. The card came assembled so no extra work is needed, but provides the Replica I with a way to save and load programs from your PC. The Replica I has no storage device so when you turn it off all work is lost. The card is designed to sit on top of an existing socket and simulates keyboard input. Through Hyper Terminal, the sending of a text file literally types the program into memory. Quite ingenious really.

Someone else has compiled a detailed account of building the Replica I from start to finish. Their account can be found here.

My setup includes: an AT power supply (a little tricky to find nowadays, but they are out there), a small footprint PS/2 keyboard, the composite video input on my Dell 2001 FP monitor, and my old Dell Inspirion 5000 laptop providing the serial connection.

You can write your program in machine op-code directly into the 32k of memory available, or you can fire up BASIC, which Briel Computers has stored into ROM for you. Very nice of them so you don't have to have the serial card and load it every time you power it up. To enter into BASIC, run the code which happens to be stored in its original memory location of 'E000' by typing:

E000R

I wrote the following program in 5th grade. It was my first program ever written on my first computer, an Apple II+. It was little more than a screen saver of sorts... with a snake-like shape bouncing back and forth from side to side as the lines scroll up with each print command... but it was amazing to me. I can't express how cool it was to reproduce it after all these years and see it bounce back and forth on my monitor, just as it did way back when.

 10 REM ---JOBY'S SNAKE---
 20 DIM S$(5)
 30 S$ = "<--->"
 40 FOR I = 1 TO 35
 50 TAB I: PRINT S$
 60 NEXT I
 70 FOR I = 34 TO 2 STEP -1
 80 TAB I: PRINT S$
 90 NEXT I
100 GOTO 40

Briel Computers also maintains an archive of some original games and programs written in the mid 70's that have been saved from cassette tape and are able to be loaded via the serial port.