well I get what you're saying, but even after spending a nice chunk of time doing cruise stuff, I've gotten to the conclusion that on every vacation there's some dead time.
I'm not gonna play that much either, I'm taking my PSP with me and I have a bunch of games there, as well as some movies and a book, but it's 8 days without much internet so, I need to be prepared to kill boredom. 🙂
While I'm out on expeditions it's great, and while I'm hanging around inthe cruise it's cool, but when you're at a hotel room with expensive internet or in the cruise cabin it's nice to have options.
Do you have Bootcamp? If it's single player stuff only then you can't go wrong with HL2 and the episode sequels. Or if you can get multiplayer running then TF2 and L4D are addictive as hell (if hell was addictive).