We've done Tulum, Xel-ha, Chankanaab Park swim with the dolphins, Fat Tuesdays for wonderful Margaritas, shopping, 2 snorkeling trips through the ship.
We just got back from Cozumel on Saturday. We shopped in the morning, ate lunch at Margaritiville and went to Chankanaab Park and snorkeled in the afternoon. It is beautiful there. I could have spent the whole day there.