MITS Altair 8800 (1975)

It sported blinking lights and toggle switches, and you assembled it yourself from a $397 kit sold by an Albuquerque mail-order company that had formerly been in the model rocket business. The Altair was, in other words, a gadget, but it was also the first popular home computer. Not very useful at first, it soon inspired an entire industry of upgrades, peripherals, and software--and prompted computer geeks Bill Gates and Paul Allen to form a company to sell a version of the BASIC programming language. (They called their startup Micro-soft, later ditching the hyphen.) Also present at the creation: MITS documentation manager David Bunnell, who went on to found a bevy of successful computer magazines, including PC World. The Computer Science Club at the University of California at Davis has more information, including a photo of the MITS.