You'll have a great time on the Explorer. It is a wonderful ship and we had the best time on it. We sailed a few weeks ago. But, I would suggest you see all the shows (the comedians are great) and also the ice show. Also, they have games for adults that are hilarious - I would definitely go to those for a great laugh! I would suggest reading some of the cruise reviews and getting an idea of what to expect so you can kind of plan out your week on board!
Hope you have a wonderful time and write when you get back - look forward to hearing what you thought of the ship.