Spread Fan
Start Hold the hand out so that the index finger is parallel to the ground and the palm is perpendicular to the ground. Hold a stack of three coins flatwise between the index finger and the thumb. The bottom of the stack should be on the upper edge of the index finger.
Directions
  1. Slowly push the thumb away from you so that the top coin slides over the middle coin about half its width.
  2. Now push the thumb down so that it contacts the middle coin and now you can push the middle coin out half its width.
From here you can reverse the moves to get back to the start.
Comments For the best effect try to minimize the amount of coin that you grab with the thumb so that the coins can be clearly seen.

You can increase the amount of coins but there is a limit. I can create a nice fan with up to eight 50c pieces. Any more than that and I end up with the bottom coins not fanning properly.

Make sure the fan is formed with one smooth motion of the thumb.