Those shooting games you get on consoles - like Point Blank or Time Crisis - how do they work, because it’s, like, you know, just a TV, but it registers stuff when you shoot at it.
It actually works “backwards”, as I understand it. When you pull the trigger, a white flash briefly appears at the location of the target (ie, whatever you are meant to hit). It’s the gun that does the sensing - if the gun picks up white light, then it knows you were aiming at the target.
This means it should be possible to cheat by aiming at something else the right colour, but I’ve never tried this cos I haven’t got a light-gun 
On preview, looks like someone else has provided a cite, which will no doubt prove me wrong…
I’ve got a cite, too.
And annecdotally, I can say that I have managed to hit the ducks by aiming at a light bulb, but it’s not reliable. Apparently, the gun is specifically looking for a flash of light, not a steady source.
On the old games, you could often see the white squares at the moment you pulled the trigger. I haven’t played the newer light gun games in a while, but I would assume it doesn’t look so hokey. . . Do they paint the whole screen white as described in the howstuffworks article, and disguise it by incorporating the white flash into some kind of “muzzle flash”-type animation (squeeze the trigger, hear gunshot and see bright flash followed by a quick “fade” back to the picture)?