Card Manufacturer: Cadaco
Card Set: All-Star Baseball Game
Card Number: NNO
Card Type: Base Disc
Cadaco has been around a long time, since 1941, but it wasn't until 1989 (edit: make that 1988 thanks John) that they started putting player images on their discs. And once they did the discs took on a whole new level of collectiblity.
I won't go over how the game is played but basically you put your player disc in a spinner and spin. The numbers around the outside of the disc correspond with different batting actions.
I'm a sucker for oddballs, especially round ones.
Here's what an example Batting Key, I'm not sure if this is for the 1990 set or not.