The Shake-a-Face was a fun vintage toy that involved shaking a small plastic circle to create different facial expressions on ... more fun because it's always a surprise. This would also be ...

Affectiva’s basic program analyzes the face 20 times a second for 46 localized expressions of happiness, sadness, surprise, fear, anger, disgust and contempt, plus interest and confusion.

Practise your facial expressions in front of the mirror so you can see how you interpret different emotions. Do you overact? Is your puzzled face too similar to your surprised face?