A staple of 1960s TV was the blinky-light computer panel. On shows like Batman and Lost in Space you'd see a giant panel of indicator lights, madly indicating...something technical. One iconic real-world computer, the Burroughs B-205, was used in dozens of shows and movies. On some shows you'd have just the lights; on others, the B-205's massive tape drives showed up in the background, sometimes mixed in with other computer gear. As late as 1999, the B-205's tape drives appeared in Austin Powers: The Spy Who Shagged Me.
So how did the B-205's blinking lights work? In this video, prop builder Brian Mix explains how he built a replica, including hand-wiring the blinking patterns (after learning them by freeze-framing Lost in Space). If you've ever wondered what made the original Batcomputer tick, or whether the patterns actually mean anything (they don't), check this out:
If you have the patience to make this kind of thing, check out the Lost in Space Props Yahoo! Group. If not, here's some footage of another B-205 replica: