Quite a few years ago, I started out planning a trip to Arizona and ended up going to Spain. I'm sure other people do this - Dave and I talked about going to Mexico for Christmas and, after looking at airfares and schedules, we bought tickets to Albuquerque over Thanksgiving.
Ray had several half days of school before a 4 day weekend so we didn't mind having him miss a few days of classes. It is his senior year and he stays caught up, even though he is pretty good at turning in his assignments at the last minute. :-)
We rented a car and drove up to Los Alamos and Santa Fe. We focused on science, history, art and Mexican food. It was a great trip!