I Doubt It is a cheater's paradise of a card game since the object of the game is to cheat as much as you can. Use one deck of cards for up to four players.
- Deal out all 52 playing cards as evenly as possible. Deal one card at a time to each player, rotating in a clockwise manner until all the cards are dealt. For each game, rotate the dealer to the left. That way, each person takes a turn having an extra card or two.
- Take a minute to let everyone organize his or her cards.
- Have the person to the dealer's left play first and start with the aces. The next player will discard 2s, the following player 3s and so forth. Start again with aces after kings have been played.
- Play up to four cards of the card you're required to discard. Lay the cards face down in the middle of the table, announcing what you play as you do it. You don't necessarily have to play the cards you announce.
- Allow a moment after each person plays to let anyone challenge the person who played the cards.
- Challenge a person if you think he might not be discarding what he says he is by saying "I doubt it."
- Look at the discarded cards if there's a challenge. If they are what the person who played them said, then have the challenger pick up all the cards in the discard pile. If they are not what the person said they were, then have the player who discarded them pick them all up.
- Play even if you don't have the required card to discard. You cannot pass.
- Win by playing all of your cards first.
The trick to this game is knowing when you can fool your opponents. If you hold all four queens, play four random cards and say "Four queens" with confidence. Since no one else has any queens, no one will (usually) challenge you.
The longer the game goes with no challenges, the bigger the center pile the cheater - or the challenger - will have to pick up.
Use two or three decks with large groups of players. Use two decks for four to eight players; three decks for a crowd. A person will be able to discard up to 8 cards with two decks and up to 12 with three decks.
Play a variation of I Doubt It: Allow the person who wins a challenge to name and play a new rank to continue the game. You may also allow players to pass if they don't have a card to discard.