Find the Red, White and Blue
Using enough ping pong balls to equal 3 balls for each guest; attach red, white and blue sticky dots (from your office supply store)- one dot per ball.  You should now have an equal number of red, white and blue balls.  Hide the balls in the yard, like you would easter eggs.  At the count of 1-2-3 the guests start the hunt.  The object of the hunt is for the guests to find a red, white and blue ball.  The first guest to find all three wins the game!!