What's the best family vacation you've taken that's been fun and educational?

Our best vacation was a three week vacation to the caribbean for our 16th aniversary. For the first week, we went to a family resort in Antigua where our son took Royal Yacht Club sailing classes. Dad and I had access to water toys and full time day care, but by the end of the week our son (9) was sailing single handed in the bay. For the next two weeks, we chartered a yacht and sailed all around near Mystique (where Mick Jagger and David Bowie live) and anchored near Tobago Cay reefs and snorkled all around. We also took a sea kayak so our son could go to shore and play in the sand. He loved the freedom. He learned so much and even learned to dive when we were at anchor. It cost a lot but was worth it. We don't do this every year, but it really helped our family and created life changing memories for all of us. It is a lot of work though. Prior to leaving we studied reefs and identified many turtles and fish. Most importantly, my two guys really had fun together and we had to be a real team the whole time. No slackers on this vacation!
At the resort we were the only Americans and the European kids loved him and imitated his accent.

Another trip that was great was Costa Rica. We studied the rain forest, volcanos etc and took a ride in the canopy where they filmed Jurassic Park. He loved it. Everyone was very friendly and it was a very international place with families from all around the world.