t's summer, and if you're not interested in the usual outdoor activities like hiking and biking, it's the ideal time to pick up a water sport. Some water sports, especially ocean ones like surfing, are seasonal or time-specific, but others you can take to indoor pools, or lakes and rivers. A great indoor or outdoor cardio water sport is swimming. It isn't hard on your joints (unlike running, which can be a knee-killer) and the water provides more resistance than air, so it helps tone your whole body. If you live near the ocean or any other large body of water, you can learn to surf, body board, or water ski, which, like its snowy counterpart, can provide a good workout. You might also pick up more obscure tow sports like wakeboarding, kneeboarding, and scurfing. If exercising in a bathing suit isn't your thing but you like being active and social on the water, rowing sports like kayaking, white water rafting, dragon boating, and canoeing might be for you - and they kick the muscles in your upper body in gear and into shape. Even if you can't keep up with the sport for the rest of the year, where there's water, there's probably something interesting and active to do, too. You get the rush of meeting new people and learning something new while enjoying the summer weather.