We also do one in addition to serenading the bride - we serenade the groom. We form a circle - bride included in the circle - and put him in the middle and sing "Put Him in a Corner" (what we sing during candle passings - well, before they were outlawed). One by one we go around the circle and step in to kiss the cheek of the groom - or hug him if we don't know him that well. The last one to go to the middle is the bride, who gives him a good kiss.
The boys seem to like it.