The Parks Department is announcing kayak rentals for Central Park's lake today. The Lake will have three kayaks available for $12/hour, so the Lake will be full of kayaks, rowboats, and gondolas - plus some birds hanging out. Here's the Parks Department's recreational boating map - there are kayaks for rent in three other parks, but if you have your own (you know, kayaks are convenient in your NYC-size apartment), there are kayak launches in all five boroughs. Wonder if the Mayor will demonstrate his Eskimo roll one of these days.
But if you're interested in some free kayaking - as well as possibly dirtier and certainly brinier waters - the Downtown Boathouse's free kayaks are available until October 15. Their locations are along the Hudson River - at Pier 40, off Houston; Pier 96, off West 56th Street; and at West 72nd Street (photograph, above). You sign a waiver that's valid for the whole year and once you get a life jacket/safety vest, you're good to go. Just wear clothes you don't mind getting soaked. And for kayaking in the East River, check out the LIC Community Boathouse.