Here is a blast to the past... Play the original text adventure game for 'The Hitch Hiker's Guide to the Galaxy'. It's great fun, but its requires a Java-based browser to play.
To access the game go to the web site. Go to the bottom of the screen, type "851108" and press the the OK button.
If your browser supports Java, it will load within your browser. Then read the page for the basic instructions on how to play the game.