The very first video game
"Tennis for Two" is the name of the very first interactive video game and it used an oscilloscope for a screen.
The game was created by American physicist William Higinbotham a.k.a. Willy in 1958.
He discovered how to make the game while reading the instruction manual for a Donner model 30 computer used by the US government. The analog computer could calculate missile trajectories (or a bouncing ball) with wind resistance.