Trivia was in the Casino on the Carnival Victory too. :/
DH and I are big fans of board games so if we end up being bored, you'll probably find us in the library... or napping.
Technically, we have nothing going on on Nassau day except going to the pool (I've been checking every week in the excursion section, so far, absolutely nothing convinces me to book one), but we'll definitely be off the ship on HMC & GT if weather permits.
I'm mostly worried about the sea day. I tend to get bored on sea days, no matter which cruise line I'm on. But since Carnival is cheaper, I feel less guilty to nap so there's that. :/