Buy a bag of baloons, and place in a bowl.  Have each guest pick a baloon.  Don't forget your hostess.   Now tell them the first one to blow up the baloon, tie it and sit on it and pop it will win a prize.   This is a great one to get them moving and laughing.  They will have a great time.    
 
If anyone has any great games you use and have a lot of success with, please share.  Others could use your suggestions.