Roatan is my favorite port because it reminds me of Hawaii in the old days and I love all the native wood work you can buy. I bought a smallish hand made bowl of mahogany and a wall thingee, and some Lenca pottery. The lenca pottery was very cheap compared to any other port for a similar sized fish I bought. The fish I bought for $16 on sale would have been $50 for that size of a fish made of anything in any other port I've visited. I find Roatan so cheap and love bargains. Its very beautiful there too. We did victor bodden once .. and twice we just grabbed a cab.
Lenca pottery has a very distinctive look you can't miss
You can get private tours very cheap for all day, about $35 pp. We spent all day doing non swimming things. The iguanna santuary, the monkeys at Victor's house and on and on.
Belize is almost always included with Roatan. You can buy any drugs you want over the counter!!! (Ok I dont have insurance, so I do). The best thing here to me would be to see the ruins. The city is kind of awful.
For more unusual ports.. I am doing a B2B on celebrity out of san juan next year. I dont know if air fare is a consideration, as its a bit more expensive to fly to san juan, but I will see ports that are not on the usual routes of call.
Maybe you could give us more to go on. Do you like to hike or walk? A walking tour like in Nassau. (free), but to me Bahamas are ugly and brown and boring compared to more mountainous ports.