in 1976, New York City was contemplating lifting the ban on pinball. To prove to the city that pinball was a game of skill, an experienced player named Roger Sharpe was brought in to demonstrate how he could control the ball and accurately predict his shots. The city council was convinced after he successfully called his shot ala Babe Ruth in the middle of a game and decided that there was enough skill involved for pinball to fall outside the laws governing games of chance.
Ceramic "powerballs" were used in some machines - normally as special, unlockable bonuses. Since they were much lighter than the steel balls, they traveled much faster. This made for a more exciting game.
Originally, there was no spring powered plunger in pinball. Like billiards, players had a cue stick with which they would reach into the apparatus and strike the ball. The game was very similar to pool or billiards today, with balls that one had to sink in pockets around obstacles. Well, sort of like billiards. Billiards with beer bottles on the felt.