After trying out the new Fortune Cards at D&D: Encounters and mulling it over for a night, here is a review of what I think of them.
Overview: The description of the Fortune cards is as follows: "Fortune takes many forms. The hand of fate, destiny, divine intervention, or even just plain luck—adventurers attribute their good (or bad) fortune to such agents. DUNGEONS & DRAGONS Fortune Cards™ represent these forces acting on your character and his or her allies. Try using these cards in your DUNGEONS & DRAGONS® roleplaying game. May fortune favor you!" (taken from http://www.wizards.com/dnd/files/FortuneCardRules.pdf) Each player brings their own deck, and the deck needs to contain any multiple of 10 cards. There are three types of cards: Attack, Defense, and Tactics. There needs to be at least three of each type of card in a 10-card deck, 6 of each in a 20-card deck, and so on.
At the start of an encounter, each player shuffles their deck and draws one card. You are only allowed one card in your hand. At the start of the turn, the player can discard their card to draw a new one, draw a new card if there is not one in your hand, or hold on to the current card. One card can be played per round, and the cards say when they can be played (i.e. while attacking, when hit, etc.). The card requires no action to be played.