The Colour Changing Deck is a nice effect by Gianfranco Preverino.
You open a blue box of playing cards and take out the deck. The spectator chooses a card which is placed face up on the table before it is revealed to be the only red card. It is placed back on the blue deck but then a moment later the second card also turns red, the deck is fanned to reveal they are now all red. As a final move the box is made to change colour from blue to red.
Everything needed to perform the effect is supplied and their are online instructions supplied via a link.