Pong

Pong is a one- or two-player competitive game, produced by Atari and —

— no, you know what? The hell with that. It's Pong. It doesn't need an introduction. There aren't even any videos of Pong on the Atari 2600 on YouTube, and you know why? Because everyone already knows what it looks like.

(Here's one of the original arcade version, though.)

I actually first played Pong on the Atari video computer system, which is what they called the 2600 before they called it the 2600. I couldn't have been more than four — I have vague memories of playing it sometime before I moved to Texas. Yes, I played it with the paddles — pushing buttons or twiddling tiny thumbsticks just isn't the same; half the fun was putting your whole arm, if not your whole body, into twisting the controller. (I bet you could do a nifty Wii version, though.)

Also it still inspires people, although this is probably not saying much; nostalgia often does.

Tangentially, here is a video of Welshmen doing mildly inappropriate things with sheep and sheepdogs. (Also appropriate things with LEDs, because sheep are kind of hard to see in the dark.)