Maldives
A private sandbank dinner is exactly what it sounds like: the resort takes you by boat to a tiny exposed sandbank in the middle of the ocean at sunset, sets up a table, chairs, and usually some torches or candles, then leaves you mostly alone while they cook nearby. You get the whole absurdly beautiful scene to yourself for a couple of hours. The food is typically a set multi-course meal (often seafood-focused) served by one discreet waiter who stays at a polite distance. It's romantic if you're into that, or just genuinely peaceful if you're not. Expect bugs at dusk, occasional wind that can knock things over, and the very real possibility that the sand gets everywhere.
Best time is December to April when the weather is driest and the sea is calmest. May to November can work but the monsoon brings rougher water, more rain, and higher chance the sandbank is underwater or the trip gets cancelled. Expect to pay around $450–$850 for two people depending on how fancy the resort is and what's included (drinks, photography, etc.). The cheaper end is still decent; the expensive end mostly buys you better wine and nicer table settings.
Tip: always pick the wine pairing if it's offered — the food is usually good but not life-changing, while the setting makes even average wine taste excellent. Skip the photo package unless you really hate taking your own pictures; the waiter will usually snap a few decent ones for free anyway.