It's hard to imagine, but the computer mouse celebrates its 40th birthday today, making the rodent susceptible to premature over the hill jokes. The one-button wooden mouse, which was built by Bill English, was first used by Douglas Engelbart on this day 40 years ago in a demonstration at the Fall Joint Computer Conference (FJCC). Dr. Engelbart showed how the new input device could be used to clip text files, copy and paste, and how it could come in handy on computer networks.

Many of the researchers behind the first demo are reuniting to celebrate the mouse's 40th anniversary. Among them will be Dr. Rulifson, who joined the group that Dr. Englebart assembled at the Stanford Reseearch Institute in California.

"I met Doug and got throroughly enchanted," Dr. Rulifson told the BBC. "I really understood what he was after. I was blown away by the ideas."

Forty years later and the computer market is overrun with rodents, although the mouse has evolved quite a bit from its one-button debut. Logitech alone has shipped over a billion mice found in over 100 countries, and should probably send English a 'thank-you' card.