What was the first video game ever?

Depending on the definition of "video game", there are diverging answers: "Spacewar!" (1962), "Tennis for Two" (1958), "OXO" (1952)...

Perhaps the best answer is "Bertie the Brain" (1950), which some exclude from video game consideration because it used light bulbs as a opposed to a graphical screen. Bertie, the brainchild (no pun intended) of Jewish Canadian engineer Josef Kates, played tic-tac-toe against a human opponent. It had various levels of difficulty, and was virtually unbeatable on the hardest one.

Today, when video games beat humans at chess and Go, winning in tic-tac-toe might seem insignificant, but it all had to start somewhere...

Oh, and Kates also invented the world's first automated traffic light.

There are no diverging answers about that one...