We did the Disneyland Parc tour in February, which I secretly booked ahead of our trip. As I hadn't told any of the family about it, they all walked up to our Guide (Joost) at the beginning literally not knowing what they were letting themselves in for - their faces were such a picture (I think they were all scared I'd set up some kind of stage performance for them to do or something!).
The tour itself was fantastic, starting at the entrance area and working up Main Street, before going through the other Lands. You discover the history behind it all, as well as the planning, design, hidden 'in-jokes', etc. It was actually fascinating, which I definitely didn't expect - I just thought it would be something a bit different that we haven't done on any of our previous trips!
Highly recommended.
Also, the first people to book a particular time slot get to choose the language of the tour. We had a Dutch family with us but they obviously spoke very good English (just for a change, LOL).