TEXT: 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!
  HOW TO PLAY
  You can use all the cards of one or more 
  DUNGEONS & DRAGONS Fortune Cards 
  boosters as your deck. Each player brings 
  his or her own deck to the game.
  At the start of each encounter, shuffl  e your deck 
  and draw a card.
  You can play one card per round. It requires no action to 
  play. The rules on each card state when you can play it and 
  what eff ect it has. A card takes eff ect just once unless it states 
  otherwise, and you discard the card when its eff ect ends. 
  You can have only one Fortune Card in your hand at a time. At the 
  start of each of your turns, you can do one of the following:
   
  ✦  Discard the card in your hand and draw a new one.
   
  ✦  Draw a new card if you don’t have one in your hand.
   
  ✦  Keep the card that’s in your hand if you haven’t played it.
  TM & ©2011 Wizards of the Coast LLC in the U.S.A. and other countries.
  
  BUILD YOUR OWN DECK
  You can also build and play with your own customized deck of DUNGEONS 
  & DRAGONS Fortune Cards™. Each card in the Shadow Over Nentir Vale™ set 
  belongs to one of three categories: Attack, Defense, or Tactics. The card’s 
  face displays its category.
  A custom Fortune Card deck can contain any multiple of 10 cards (10, 
  20, 30, and so on). For every 10 cards in your deck, you must have at 
  least 3 cards of each of the three categories (Attack, Defense, Tactics), as 
  shown in the table below.
  Deck Size 
  Minimum Cards per Category
   
  10 
  3
   
  20 
  6
   
  30 
  9
  And so on.
  FAQ 
  The DUNGEONS & DRAGONS Fortune Cards
  rules and FAQ are available at
  DungeonsandDragons.com/fortunecards.
  M1831602000001  EN
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/D&D 4th Edition/Fortune Cards/Fortune Cards - Rules.pdf