Equipment:
A volleyball
A net

Description:
Volleyball is a great family activity that kids of all ages can enjoytogether.
The rules are simple: Keep the ball off the ground and going back and forth over the net. Each side or team can hit the ball three times maximum before it has to go over the net. Play until one team reaches 11 points.

It's a good idea to mark off the boundaries around the net and ideally there are 6 people per team. This game is great for large groups of people because you can take turns rotating in after each serve.

Other comments or suggestions:
You can make your own gold, silver and bronze medals with construction paper and ribbons.
Or rewards can be food based: ice cream, cookies, and chips.
Or rewards can be chore based: 1 free night no dishes, 1 free day of not making your bed, 1 extra hour of TV time.
Have fun with it. Let the family decide beforehand what today's Olympic rewards will be.