I look at a cruise as a spa vacation so love seadays as
the Caribbean ports bore after awhile.

I bring out the inner child in me by participating in all
the free games plus there's always bingo. Do not poolsit;
and usually go to the dining room rather than the Open Deck
for a nice lunch. And then there's nap time if I have
been over-served in said DR.

There are activities - like wine tastings, martini demonstrations - sometimes actually interesting and usually designed to get you to buy something at the end - but usually not in a pushy way.

We usually used some of the time to plan what we were going to do at the next port.

We have cruised twice with our almost-adult kids when they were under 21 - and although all had a great time, 17-20 is sometimes a little more difficult age to find something to do on a cruise - they are too old for kid activities and not quite old enough for some adult acitivites - are not allowed into bars, some dance club type things after a certain hour. Also depends on how outgoing they are - our daughter always met people her own age, our son did not.

Another suggestion - kids that age are often very tied to their electronic communication devices (cell, internet, etc) - research ahead of time availability of these connections which will likely be either unavailable or very expensive.

I wondered the same thing as you about how to spend time - but always found something to do. Daughter and I even ended doing things like watching the "Mr Sexy Legs" contest once - something I would be the first to deem tacky and trashy if it were to have occured in the real world.

Sea days are my favorite part of a cruise. My cruise last August had 4 sea days. I did a variation of these activities on each of the days:

spent some time reading on one of decks,
leisurely breakfasts and lunches (or brunch)
played card/board games in the game room with my daughter,
went to the cinema to see a movie,
attended various lectures or shows,
did several wine tastings,
got spa treatments,
spent time at the library,
went to the art auction for a free glass of champagne,
window shopped in the shopping arcade,
played bingo,
worked out in the exercise room,
had early evening drinks and tapas in the piano lounge before dinner,
took a nap

Sea days always go by really quickly for me and have me wishing for more.

I love cruises with several sea days. Only on sea days, you can enjoy the ship thoroughly. Every ship offers many more activities that you can participate in. There are so many choices - nobody gets bored on a cruiseship.

Once, we made a three-week cruise with many sea days, at the end four sea days in a row. They offered workshops where we built models, they offered dance lessons, lectures etc etc. We never managed it to view a film during a cruise - although each vessel has a cinema, often with popular movies.

Usually cruises gives out itnerary sheets that explains what activities/shows are available on what day and time. The staff either puts in the cabin the night before or you can pick one up at the Pursers desk.

We don't do casino, spa and pool. Never been in the pool or ot tub once despite years of crusing. Forget about the kids for a moment, here is what DW and me would do on a typical sea day.

get up early, catch the sun rise on the horizon. Get soem fresh air, go back to bed. Get up late, have breakfast or lunch. Go to attrium or piazza (or lobby) and relax, have a coffee, listen to the live music (piano player or a quartet)

People watching, browse the shops, take in lectures from the featured guest speaker or naturalist. Walk around the ship, borwse the shops. (my DW loves to browse the shops) A relaxed dinner, catch a show, maybe go to club and do more people watching.

In between, there is ping pong tables, mini golf, bridge, library, ships tour, afternoon show etc among other things.

The Princess ships also features "movie under the stars", a throw back to the old drive-in except much much better. Sitting on deck chairs, the crew brings pop corn, drinks, coffee, blankets ... watching a show on the 100 foot big screen almost as wide as the ship. (Love to catch the Monday night football on the big screen ... )

On a big ship, there is not enough sea day to enjoy everything that the ship has to offer. We were on the Ruby and after 7 days, we still haven't been to every place!

We dopn't like very many sea days--the ship is priomarily a floating hotel for us. That being sid, on a port intensive European cruise, it's nice to have a rest every few days.

We sleep in, have a leisurely breakfast, take a walk, participate in some activities throughout the day, perhaps nap in the shade by the pool, read, plan for the next few days.

Sleep late, book a massage, set aside a couple of hours for sun bathing/lounge by a pool, plan to attend a couple of fun activities (dancing lessons/trivia contest/ lectures/racketball tournies/bingo/cards games/special ship tours), select a DVR from Film Lists and watch in bed, watch the Feature of the Day at the Ship Theater, learn to use one of the zillion gym machines, take yoga class, take Health Seminar of the Day, shop in the Ship Arcade, explore titles in the library, surf the net......I just returned from a cruise and the SEA days were exhausting !