Few people have heard of it, yet many consider John Blankenbaker's KENBAK-1 to be the first commercial personal computer.
Pong System With Alarmingly Realistic™ Gun
By bohus
Once Pong technology had been harnessed for the home, the proto-video game spawned like mad. 
Many manufacturers used the same Pong computer chip in their early game consoles, so the video gaming market of the mid 70's was flooded with cheap Pong clones. They mostly had the same Pong variants built in (hockey, squash, etc), though some units also included a target shooting game.
The Radio Shack TV Scoreboard has two target shooting games, cleverly labeled "target" and "skeet". Basically you take aim at a bouncing white block on the screen with the alarmingly realistic (no, I'm not referring to the "Realistic™" house brand at Radio Shack!) handgun. No gun sound effects either - just a simple beep when your virtual bullet meets its mark.
The battery- powered TV Scoreboard is more compact than most. The main unit houses the game selector, speaker, and controllers for one player - the other rotary controller can split from the main body which is also where the shiver-inducing gun plugs in. It's hard not to notice the distinct resemblance to an old-school gray brick cell phone. Boy, I'm glad that gaming has moved on since 1976.
related:
TV Pow - video games via phone in the 70's
Build your own Pong game
Atari Pong - stirrings of the home video game revolution
Pong on the Xbox 360
