Hold down Command-Option-x-o right after you turn on or reboot the machine.
The Classic starts up from a minimal ROM-disk which contains System 6.0.3, Finder 6.1x, and AppleShare.
(This version of the System is not recommended for use with the Classic, so you probably shouldn't boot off it to do any important work.)
If you look at the ROM-disk with a program able to see invisible files (like ResEdit or MacTools), you'll find a folder named "Brought to you by" hidden there, containing more hidden folders bearing the names of the Classic designers. (The keys `X' and `O' were chosen because the development name of the Classic was the "Mac XO", or was it OX?) Also, there's an invisible application in the System Folder named "Launch" and set as the startup application; anybody know what it does? (Thanks to Charles Gousha for more info.)
