Let me share the outline of a card effect which I saw a few days back. I really enjoyed it.
1.The performer displays four Kings and places them on the table.
2.The audience selects a card from the tabled card.
3.The selected card is turned over and displayed as Queen of Hearts. (this baffles the audience as they had seen 4 Kings)
4. The performer now picks up an envelope which lying on the table and removes a card from it and displays it. To the audience surprise it is also Queen of Hearts.
Here there were 2 effects.
I am blank about the origin of this trick.