This works any time you have the Mac powered on.
1) Hit the interrupt button on the programmer's switch. A window with a ">"-prompt will open.
2) Type in the following, without the quotes:
"G 41D89A" (or is it "G 81D89A"?)
Ta-daa! A few scanned-in photos of the entire Mac Plus crew right there on you screen, directly from the Rom.
3) Hit the interrupt again and type "G FINDER", or just reboot the Mac. BTW, you can use "G FINDER" any time you want to reboot the OS shell.
I think this works on the Mac "Nothing" (Fat Mac) as well, but not later versions.