1. A taxi tour around the island. There's nothing like seeing a place from a local's perspective, and a taxi driver is usually an excellent guide. Tell your driver how long you want to be, how much you want to see, settle on a price and off you go. He'll take you places only locals know about, and give you his unique commentary along the way. If you stop somewhere for lunch, it's polite to include him (he will not abuse it).
2. A Sunday walk with the National Trust. These are some of the least-known but most interesting 3-hour excursions you'll ever do. Morning walks start at 6am sharp (do not be late) and evening one's around 3.30pm, and they go places which even Barbadians find amazing. There are different levels for different folks. Bring your own water, walking shoes, sunblock, etc.
3. Snorkelling with turtles. Of course, you can do this as part of an organized cruise tour, but you can also do it for free, right off the beach. Just go to the mile-long Carlisle Bay beach and ask anyone. Take your snorkel and camera, but be careful of flapping flippers – they scare the turtles; and do not try to touch – they assume your finger is food and snap. But there's nothing better than seeing these graceful creatures in their natural habitat.
4. Take an off-road adventure tour. There are a couple of companies that offer this – a genuine off-the-beaten-track jaunt in 4-wheel drives through the countryside. It helps to have a strong stomach, but the guides are sassy and fun and you'll enjoy the experience while seeing a side Barbados that few others see.
5. See a working windmill. Back in prior centuries, the island was dotted with over 500 windmills for grinding sugar-cane in molasses; sadly these have all been replaced. But the National Trust maintains one in working order, and they actually use once a month during the sugar season. It's wondrous to stand underneath as the huge sails go whooshing over your head … and tasting the fresh sweet cane-juice after!
6. Go to a release of turtle hatchlings. There are few more moving sights than a hundred or so week-old baby turtles struggling to the sea; you find yourself amazed at the wonders of Nature. The Barbados Turtle Project manages the release of turtle hatchlings from nests that have compromised. They do not know too long in when another one will happen, for obvious reasons, but if you like them on Facebook they'll send you an alert. And they are very informative.
7. Take a private cruise. If you're willing to rent your own catamaran or yacht, you can cruise the seas morning, noon or night, depending on your wishes. But you can also feel like a millionaire by taking a sunset sushi-and-champagne cruise on a Tiami catamaran; numbers are limited and the experience is unforgetable (so is the food). There's no swimming, so wear your resort casual and be prepared to kick off those sandals. Cheers!