The Snap-Pen from ACM

The performer takes what appears to be a pen out of his pocket. After he removes the cap, the audience realizes that instead of a tip, this pen has a small loop of elastic at the end. "It's a small game of ability", says the performer. "As you can see, the tip of this pen has a small loop of elastic, and if you look closely inside the cap, you might see a small hook inside the cap." The performer takes the pen, and delicately inserts that loop inside the cap. Some twists and turns and the spectators can see that the pen is hooked to the cap. He pulls the pen back, and it snaps back inside the cap. Slowly, the performer twists and turns the pen a few times, and the loop is released from the hook. Quite interesting! But when the performer gives the pen to the audience, they can't replicate the magicians performance! The performer then takes the pen back and repeats the trick as many times as he wants!