Story Swap and Share
Have each adult write on a slip of paper a short story about himself that no one else would know. The story should be no more than five sentences long and ideally shouldn't be something family members or friends would automatically assume belongs to a particular person. Place all the short stories in a box and have each person take a turn choosing one and reading it aloud. The reader has the first guess as to whom the story belongs. If the reader guesses correctly, she wins a prize. If she guesses incorrectly, the story is open to the rest of the players to guess the correct person.
Murder Mystery Dinner Party
Ask all guests to come to the party dressed in costume, but specify to each of them what they should come dressed as. Choose characters such as French maid, rock star and hippie. Decide beforehand who will play the killer and who will be the game's victim. Choose the murder weapon beforehand as well, but include some others to throw the guests off, such as a butcher knife, gun, mallet and bow and arrow. Coordinate with the two guests in on the game to decide how the murder will be pulled off. The host will play the detective to guide players through the game and set up clues for other guests to find. The guest who solves the crime first wins the game.
Stand-Up Standoff
Set up a real or fake microphone and set chairs around it in a semi-circle. Have party guests try their hand at stand-up comedy with turns at the microphone. Prior to the comedy, serve a cocktail hour, which will help guests loosen up prior to entertaining and being entertained. Include a prop closet for the performers to work from, if desired, which will add to the eccentricity and creativity involved in the performances. Take a vote afterward, either by loudness of applause or by secret ballot, to determine the winner.