A colleague at work confided in me, over beers, that he and his girl started out with nudist cruises but have "graduated" to "Lifestyle" Cruising. I had never heard of this.
Nudism cruises are fairly sedate, it seems, but for "Lifestyle" the organizers charter a cruise boat for a few days of an orgiastic circus.
Lose your inhibitions, etc., I suppose. It does not sound like a New England Yankee sort of thing. They make you bring a heterosexual date for sharing. I don't think these things exist for gays, but who knows?
I checked out a couple of links:
The Swinger Cruises
Couples Cruise
Lifestyle Cruise
I think I'll pass.