This works on an early 80's computer--the Commodore PET. If you type in: "WAIT 6502,0" (without the quotes), the screen will fill with: MICROSOFT!MICROSOFT!MICROSOFT! This machine from 1979-80 used a version of the BASIC programming language written by Microsoft before anyone heard of them. '6502' is the type of microprocessor the machine used (which incidentally the original Nintendo entertainment system used too) If you vary the number after the comma, the number you put in is the number of times the machine prints MICROSOFT! on the screen. This I think is one of the very earliest Easter eggs.