Take the ferry to Centre Island and rent a bike then head to Ward's Island (they're connected). Stop for lunch and a drink at Rectory Cafe, they even have bike parking. It's great. There's a hippie village out there and you can race kids on scooters. Fun.
If you're bringing your wife, get the penthouse suite. Totally amazing and has it's own private rooftop deck (and huge puffy lounge seat for two, with a fire pit if it's cold) with a great view of the city. They also have a great scandinavian spa on site. Love the ambiance of this place.