Nick Trost's Australian Aces is quite possibly the best monte on the market!

You openly display four cards (three Aces of Diamonds and an Ace of Clubs). You then ask the spectator to follow the black Ace. To make things easier for the spectator, you remove one of the red aces and set it aside, face down on the table. You show the remaining cards (two red Aces and a black Ace) in your hands. Next, the black Ace is put between the other two red Aces. The spectator fails to follow the black Ace because when the three cards are shown, they're ALL RED ACES and the black Ace is now on the table! The entire routine is repeated-but again the spectator cannot follow the Black Ace because it has ended up back on the table!! Now for the best part! The third time the spectator guesses the black Ace is on the table, but it's really a red ace... and the other three red ace cards are now ALL BLACK ACES!