A VERY POPULAR EFFECT FOR CHILDREN.
On your table is a wooden frame depicting a brick wall with a door on either end. Show that there is nothing behind the doors. Place a cut-out of a rabbit behind the right door. When talking about the naughty rabbit, a series of silly animations takes place and the rabbit runs from one door to the other, peeking out from behind every time you and the children try to catch him. Comedy abounds because you are wrong every time. Eventually, the rabbit vanishes.