You could kayak or canoe for exercise. Orrrr you could let the wind do most of the work for you--and save all the cash you were going to drop on a sailboat--with the Serenity Upwind kayak & canoe sail rig. The compact and portable system straps on to nearly any model of either boat, and setup requires no tools or modification of the vessel itself. The sail rig includes outriggers and leeboards designed to maintain stability and provide lateral resistance when fishing, standing up, or sailing into the wind. It also allows for paddling normally when there is no wind.
A telescoping mast and boom are small enough to fit in a car, with the entire Serenity Upwind set weighing 22 pounds. Extended, the rig's mast is 12' tall and its sail 40 square feet.