Well, The classiest game that I have known has to be PONG!
At first site you think that this game looks stupid, Just two bars which are on the side of the screen but as you start playing you instantly know why it was a hit in the ’70s.
You would be surprised to know that there are over 4000 pong games on that Apple App Store even today! (P.S:- As a developer it was also the first game that I made).
Here are some screenshots that you can refer to:-