This will teach you how to magically link 2 ordinary playing cards.
Step 1: The Set Up
Make a small rip on the side of 1 of the playing cards.
Step 2: Rip Out the Center
Then fold the card in half and rip out the center.
(This gives you 1 card with a hole in it and 1 with a rip in the side and a hole in it.) see pictures.
Step 3: Finish
Now while covering the rip in the side of 1 of the boxes bring them together. let the 2 slide together and then with a sharp movement pull them apart and let go of the one that is not ripped so that it hangs in space.
Then "rip" apart one card to separate them. What you acutely do is pull apart at the existing break. Throw every thing out for inspection and watch as the praise comes in.
Note: also you can do this with business cards!