Light guns hit home video game consoles with Shooting Gallery on the Magnavox Odyssey in 1972. Because the included shotgun-style light gun was only usable on a Magnavox television, the game flopped. The Nintendo Entertainment System (NES) Zapper then fell into the hands of American kids in October 1985...
A light gun that worked with all TVs was also included with the Telstar Ranger console (a pong game console developed by Coleco and distributed by Sears) in 1977. The gun was used with the skeet games supported by the console and worked pretty well at a distance from about 4 ft (although tracking a large bouncing white block on a black screen was probably not that technically challenging).
http://en.wikipedia.org/wiki/Telstar_%28game_console%29
Incidentally, my brother and I had our Telstar Ranger gun (black plastic, very gun looking) confiscated by airport security when we, perhaps unwisely, tried to carry the console, paddles and gun in our carry-on.