What does a groomsman do in the wedding?

My cousin and her fianc� are getting married, and to my delight, I was asked to participate in the wedding ceremony. I am going to be a groomsman. Does a groomsman do anything during the wedding? For example, the best man gives the ring to the priest or rabbi when it's time, but do the groomsmen and bridesmaids do anything to that extent during the ceremony?