We have some friends who do not have kids. Yet they have one of the most fun Christmas trees around! (They actually have more than one!) We began a tradition a few years ago of going to see their tree(s) sometime during the holidays. We have not gone every year but every few years. This year they had gotten a new house, so we wanted to make sure we got to see their tree and their new house.
They had also gotten a huge new tree this year. They decorate with all sorts of fun ornaments including Disney characters, Wizard of Oz, Looney Tunes, Harry Potter and Barbie. The husband also has a Star Wars/Star Trek tree in his office. It is always fun for us and the kids to see and hear their assortment of ornaments and it's fun for our friends to show them off. They have gotten so many that they have had to "retire" some of their older ones!