Have a shuffled deck of cards on the floor (The presenter should be in a chair). Have a person (from now on we will call him Bob) look through the deck and pick a card. Have bob place his card on top of the deck, now have bob cut the deck into six (give or take a few) piles (note where bob's card is at...on top of the first pile).
Now by simply pointing to the piles have Bob put the deck back together in a different order.
The prerequisite for this trick was to have a pinch of salt in your pocket. When you were pointing out which pile to put back to gather, you simply place a few (10 - 15) grains of salt on top of Bob's card. These grains of salt will act as ball bearings.
You say to bob, "I haven't touched the deck with my hands, correct?". And then (Here is where practice comes into play) with your foot lightly kick the deck of cards (with your right foot, slide into the cards to make them glide to the left). Now examine the deck, the place in the deck with the most distance between one card and the next is Bob's card. (The salt enables the deck to move farther)