MS-DOS

There are lots of things to try here. First of all, simply pressing RETURN will give you one of many different results every time. This program also recognizes some basic DOS commands, such as DIR, COLOR, INFO, REN(AME), DEL(ETE), VERSION, ASSIGN, PATH, SET, FORMAT, MODE, CLS, HELP, MOUSE, TYPE, all numbers, and some other things you'll have to discover for yourself. Each command will give you at least two different results, some as many as five, so try each one more than once, you never know what it might say!