This game is a good five minute game to encourage people to mingle. It requires several packets of jelly beans (depending on the size of your group).
Give each person 10 jelly beans, making sure they have a variety of colors. When everyone has 10 beans, the game starts.
People need to trade their beans with each other, with the goal of having 10 beans of the one color.
A variation involves having a count down clock when the game 'finishes' - just to add a sense of urgency.