Four Facts
In this game, each guest puts four pieces of information about themselves on a piece of paper. Three of them must be true, while one of them must be a lie. The more outlandish the truths, the less they will be believed, which is the point of the game. Each person will stand up and read their four facts, presenting them each as if they were true. The group must decide as a whole which one is the lie. It is fun to then tell the stories behind the three truths, and gives everyone a chance to get to know each other a little bit better.
Famous Couples
In this game, the point is to pair up the famous couples. They can be couples such as Brad and Angelina or Cleopatra and Mark Antony. When each guest comes in, put one half of a couple on a card and put it on the guest's back. Each person must then go around asking other individuals yes-or-no questions to figure out who they are supposed to be. Once each person has figured out their half of a couple, they must find the other person to finish up the couple.
I Never
Although this can also be a drinking game, for a mixer you may want to leave out the alcohol. Set up chairs as if you were playing the childhood game of Musical Chairs. Make sure there is one less chair than the number of people playing. One person is 'It' and stands near the chairs. He then says one thing he has never done, such as "I never go to bed with socks on." Everyone who does go to bed with socks on has to get up and find an empty chair, as the "It" person also looks for a chair. The person left without a chair is the new "It". There is no way to get out, the game simply continues until everyone grows tired of it or it is time for a new game. This is an interesting way to get to know your fellow singles.