Caroler Etiquette?

Last night when we were watching television, the doorbell rang. It was a little after eight-o-clock and the kids were just about to go to bed. My husband joked and said, "Maybe it's some carolers!" and believe it or not, it was. This was the first time in my life that I had been treated to caroling. I've always lived in very residential areas where houses are not close together, so this was a pleasant surprise. The carolers were a group of high school cheerleaders and they sang two songs for us on our front porch. When they were done, we clapped and thanked them. If I had had some candy canes on hand, I would have passed them out, but I had none. What is caroler etiquette anyway? Should we have invited them in? Made them hot chocolate? I have no idea what people traditionally do, but I feel like we should have given them something. Anyone have any ideas? I'd like to be prepared for next year...