Hi, I thought you may like this Mentalrobics exercise from Braingle.com:
-----------------
Card Trick: Missing Card

We have already learned how the phonetic mnemonic system [ For more on 'phonetic mnemonic system' go here: http://www.braingle.com/mind/213.html ] can be used to remember playing cards [ For more on 'remember playing cards' go here: http://www.braingle.com/mind/241.html ]. Once you learn this, here is an interesting trick that you can perform for your friends and family.

The Missing Card
Ask someone to remove one card from the deck. You are going to look through the deck once and then tell them the missing card. As you are looking through the deck you need to modify each card keyword as you come to it. Form a mental association with this modification. For example, the keyword for the 8 of clubs is 'cave'. You could picture the roof of a cave caving in. The keyword for the 4 of hearts is 'hair'. You could picture your friend with his hair on fire. Once you have looked through the deck and modified each keyword, run through the deck in your mind. The one keyword that has not been modified represents the card that was removed.
-----------------
For more mind exercises: http://www.braingle.com/mind/