Chicago Kayak offers sea kayaking instruction on Lake Michigan and in the Skokie lagoons, as well as trips (local and multi-day) to a variety of locations. It operates the Chicago Kayak Club, a membership club for kayak enthusiasts. No need to have your own equipment, pay the $60 membership fee once annually and use its boats for free on any trip or daily paddle.
Not into athletics? Go for romance--Chicago Kayak does sunrise paddles on the lake, evening paddles in the river, day trips to Devil's Lake, Wis., and Mark Twain-worthy trips on the Mighty Mississippi.