Laura - the rotation is in three phases. You do three weeks (Phase 1), then a recovery week, three more weeks (Phase 2), then a recovery week, then four weeks (Phase 3).
The recovery weeks aren't rest weeks. They are recovery for your muscles. You don't do any heavy lifting. The only weight work you do is some very light stuff in Core Synergistics.
Fox2star: the workouts vary from 48 minutes (Cardio X) to 90 minutes (Yoga X). Most of them run around an hour. A typical week in Phase 1, for instance, in the Classic rotation, looks like this:
Mon - Chest and back, Ab Ripper X
Tues - Plyo X
Wed - Shoulders and Arms, Ab Ripper X
Thurs - Yoga X
Fri - Legs and Back, Ab Ripper X
Sat - Kenpo X
Sun - Rest or Stretch X
A recovery week doesn't have any heavy weighted work as I mentioned above. You do Core Synergistics twice, Kenpo once and the rest is Yoga and Stretch.
Hope that helps!