The Jumping Rubber Band
Materials: A rubberband.
Hold your hand naturally and wrap the rubber band around your pinkie and ring fingers. Let the rubber band rest at the base of your fingers. The back of your hand should be facing your audience (picture #1 shows your hand from your view). With your other hand, stretch the rubber band and insert the tips of your pinky, ring, middle and first fingers into it. (picture #2)
Rest your fingers in the rubber band against the palm of your hand. Notice how all of the fingers are resting inside of the rubber band and how the band is held against the fingertips. (picture #3)
At this point, you should be able to simply open (straighten as in picture #4) all of your fingers to make the rubber band "jump" to your index and middle fingers.