The blacks and reds card trick is an easy trick to perform using any pack of cards, even from a spectator.
Before you perform this particular card trick, make sure that you separate the deck into 2 piles of cards, one having the red cards and the other the black cards. Next, put these 2 separate piles back together into 1 – but you must NOT shuffle the cards. When you begin your performance, separate the piles again laying them face down (of course your audience does not realise that the 2 piles consist of separate red and black cards).
Ask a volunteer from the audience to choose 1 card from each of the 2 piles in turn, then memorise each one and place them anywhere into the opposite pile from the one from which they were removed. Ask the volunteer to shuffle each pile, still face down, and then put the 2 piles back together, one on top of the other.
Take the deck of cards from the volunteer and confidently announce that you can easily identify the chosen cards.
All that you need to do to find the chosen cards is to look through the deck and pick out the 2 cards which are a completely different colour from their surrounding cards. This is a surprisingly baffling and impressive effect.