Telephone
This classic game will have kids in stitches when they see how phrases get distorted through word of mouth. To begin the game, all of the players must sit down in a large circle. Pick one person out of the group to start the game. He or she must come up with a phrase and whisper the phrase into the ear of the person on his left. That person then has to repeat the phrase into the next person's ear. The process continues until everyone has heard the phrase. The last person to hear the phrase has to announce it to the group. More than likely, the phrase will have changed since the first player uttered it.
Back-to-back Balloon Pop
Children all seem to enjoy the unpredictable nature of balloons, and they'll no doubt giggle throughout the entirety of this game. To start, divide the group of kids into pairs and have them stand with their backs against each other. Tell them they have to put the balloon between their backs and try to press their backs together to pop the balloon. The first pair to pop the balloon wins. You can add a twist to this game by having the pairs avoid popping the balloon between their backs while they race against other pairs to a finish line.
Double Charades
The classic game of charades gets a silly twist with double charades that will undoubtedly give your kids the giggles. Before you begin the game, come up with phrases the kids can act out and write each on a slip of paper, making two copies for each idea. Then, with a relatively large group of at least eight children, have them each pull out a slip of paper from a hat or bowl. On the count of three, each kid must act out his charade while simultaneously trying to find which person has the same charade as he does. The first pair to correctly spot each other wins the game.
Ha-ha
Though you win this game by stifling your laughter, giggles are sure to come with its ridiculous premise. The game begins with all of the kids lying on their backs, with their heads resting on other players' stomachs. Tell all of the children that they cannot laugh throughout the game or they will get disqualified. Then, with a somber facial expression and stoic vocal delivery, one kid in the group has to say "Ha." The child next to the first player has to say "Ha Ha" in the same manner; the third kid to go has to say "Ha Ha Ha." This process continues until only one kid--the one who doesn't laugh throughout the game--is left.