This will vary depending on the cruise line  but basically all of them include accommodation, meals in the main dining room, buffet(s) and some snack bars,  basic activities, use of main ship`s facilities, entertainment at the main theatre and movie theatre and port taxes.

Not included : medical expenses, most drinks, spa treatment, shore excursions, photos and other souvenirs, purchases at ship`s boutiques and shops, speciality restaurants and some coffee/snack shops, service charges and gratuities.