Here is a simple idea that I came up with that is a take off of the anniversary dance - which is done at so many weddings. It starts with the bride and groom in the center of the dance floor and all the guests are asked to form a big circle around the two of you. A slow, but not too song is played. The DJ (me) announces that different groups will be invited to enter the circle and dance along with the bride and groom but they are to rejoin the circle when another group is called into the center of the circle.
What groups are called? That is up to you, but some examples might be: your parents, grandparents, out of town guests (maybe specific cities), co-workers, high school or college friends, couples who married in the 70's, 60's, 50's (the music could even change to match the decade) – be creative! Or I can handle it all. By the way, this creates a great photo opportunity.