Sour Grapes was a quirky thing, with cardboard cutouts of bunches of grapes for playing boards, and loads of green counters/
Each of the bunches of grapes had 20 grapes in total, 5 of which were unhappy grapes with unhappy faces on them. The unhappy ones were at random places on each card.
You covered up the majority of your bunch of grapes with 13 green counters, one over each grape, leaving 7 grapes uncovered. Players then took turns in taking a grape from an opponents board and placing it on their board.
If you took a counter and the grape was a normal one, you placed it on your board and took another one, until you uncovered a Sour Grape at which point your turn ended.
The idea was to completely fill your bunch of grapes with counters you have removed from your opponent, without exposing any sour ones.
There were two main problems with this game. Firstly, in order to first cover your board with 13 counters in secret, you had to turn away from each other. After you had filled your bunch of grapes with randomly placed counters, you had to gingerly pick up your board and slowly turn back without displacing any counters. Inevitably, in putting it down, counters would slide all over the place making it easy for your opponent to just see which grapes to avoid.
The second flaw was that when your opponent was helping themselves to your grapes and placing them on theirs, you could see where they had placed them. As soon as they uncovered a Sour Grape, you headed straight for the ones they had just put down to replenish your stock.
Great game though!