Have your actors think and memorize words that might be natural dialogue starters. The more words an actor has memorized, the better he will be at playing “The ABC Game.” Remember words like, "ah” and “oh” count, and are funny ways to begin a line.
Begin by having two actors take the stage, or performance space. Ask the audience to give the actors a setting for their scene to take place (anyplace two people might be sitting, or standing together such as a bus stop or an airplane). Suggestions that force your actors to do something physical as they play the scene are great and can add more laughs (working at a chocolate factory, or playing tennis or golf). Pick obscure suggestions if offered, such as two women churning butter, or taking an aerobics class. Settings like these really add physical humor. The more experienced the actor, the more physical the scene should be.
Inform the audience that the two actors will be delivering lines beginning with each letter of the alphabet in order, one line at a time, and that the audience must listen carefully. If an actor skips a letter, or uses the wrong letter, they are out of the scene, and another actor is to take his place. Tell the audience to yell “boo” if the actor makes a mistake.
Have one actor begin the scene with a line relevant to the setting, beginning with a letter suggested by the audience. The two actors then take turns delivering lines beginning with the next letter in the alphabet until they have worked their way through the entire alphabet, and are back to the letter they used to begin the scene. If for example the letter "L" is suggested, the first line could be, "Listen to me honey, this class is going to be great!" The other actor would then have to deliver a line beginning with the letter "M" such as, "Man! I hope so, I am so out of shape!"
Keep replacing actors as each one makes a mistake. If an actor takes too long trying to think of a line, they should also be booed and replaced. Remember that this game works best when the actors are able to “stay in the scene,” meaning that their lines should relate to the scene or setting, and not simply start with the appropriate letter. If your actors can think of appropriate words to begin each line, while keeping the line in context with the scene, they will bring down the house!
Forget about being funny. Be sure your actors solely concentrate on playing the scene as truthfully as they can. If they are able to accomplish truth, under such silly constraints, the scene will be organically funny. That’s it! Now get out there and make ‘em laugh!