We have done a 'hide the ball' demo. Pull four people (children love to participate)from the spectators. Give one the ball and have all of them stand with their hands behind their back. One spectator holding the ball. Have the dog sit in front of the person who has the ball, indicating where the ball is.
If the dog is rock solid at this game, you can add spectators. If the dog is 'iffy' you have a smaller group.
We have one dog that never misses - but the ball is tucked into an arm pit. No one can see it, but the dog is right on indication every time.
Hondo Von Dopplet L Bauernhof "Hondo"- GSD
Lilie's Tug McGraw "Tug" - Golden Retriever
Maggie - Mini Dachshund (Rescue)
Lonestar Pivo - Texas Blue Lacy
Ashe - Barn Cat
Katie / APHA