Here are some of the health benefits of kayaking... it's stress-reducing and relaxing, calorie-burning, and muscle-strengthening all at the same time! It is a low-impact workout (you don't actually feel like you are working out)... but the average person burns 300-400 calories in 1 hour of kayaking. Kayaking also works most of your upper body muscles, even some core and leg muscles.
So if you live near a body of water and are looking for a fun, fitness-related activity to try out over the weekend... find a place that rents kayaks and go for a paddle... by yourself or with a friend! It'll have you feeling relaxed and fit... :)
p.s. You can also get a great tan while you're out on the water too... just remember your sunscreen!