Club SINZ is a members-only lifestyle club in Massachusetts, north of Boston. It has been running for more than two decades — the club says it has "been serving the Lifestyle community for 21 years" — and it takes visitors as well as locals, pitching itself to couples in the Greater Boston area and to travellers.

The exact address is not public. The club places itself "about an hour North of Downtown Boston and 1.5 hours from Portland ME", and gives the street to members; this listing therefore carries no address and no map pin.

Alongside the club itself it runs its own private social network, SINZ.NET, where members can meet other couples before attending.