A coffee pot, to know when it was empty
A lounge refrigerator, to catch a lunch thief
A door, which was opened via motion detection
Crows nesting outside a laboratory window
 
Correct Answer: A coffee pot, to know when it was empty

Now let's learn something…

Fed up with walking to an empty coffee pot, computer scientists at Cambridge University are said to have deployed the first webcam in 1991 to monitor the coffee levels from their desks, which were scattered across many rooms and floors. The camera provided a 128x128 pixel grayscale image of the coffee pot at a single frame per second.

Starting in November 1993, the camera's live feed was connected to the Internet and could be viewed worldwide, garnering attention from publications and radio stations around the globe. The coffee cam was shut down at 09:54 UTC on August 22, 2001 and the last picture it took was of a hand switching off its server.

The coffee machine that was last visible on camera (made by Krups) was auctioned off on eBay to the German news site Spiegel Online for £3,350. Krups employees later refurbished the pot free of charge, so it could be used at the publication's office.