This has been our tradition now for 10 years.  When we go on trips/vacations we make a special effort to find a Christmas ornament and I usually write on the box or the ornament itself if it does not already have the place and the year of purchase. 

Then we pick a special night to decorate the tree.  We light the fireplace and spice up the eggnog and try to remember each ornament and where we purchased it and why we chose that ornament.  It brings back pleasant memories and its our fun little game we play with each other.