This is a very simple trick that you can do anywhere and will surprise everyone.
Step 1: First Step
ADVICE: be careful, follow all the steps. If you don't do it right you can hurt your finger.
Ok, first you have to move your fingers to get ready. With your left or right hand catch the pinkie of the other hand.
Bend it forward and then bent it again to the interior of your hand.You have to use the middle finger of the hand to put it on the pinkie articulation so it would look more realistic.
This makes an illusion and it looks like you have broken your finger.
Step 2: Step by Step
I hope you've liked it.