Just in time for swimsuit season, Mayor Bloomberg is encouraging New Yorkers to use the city as their gym, saying it's never been easier or cheaper to stay in shape.

"New York City is a great place to get healthy and keep fit—anyone can make the parks, streets and sidewalks into their own personal gym," the Mayor said. Yeah! Just look at these marathon stair-runners! Except...watch out, because exercise might also destroy marriages. But should you decide to risk your holy matrimony, check out the Mayor's Be Fit NYC initiative, which encourages city dwellers to take advantage of parks, playing fields and other public athletic facilities to get fit (here's a handy infographic with tips on how to use the city); plus, you can always take the stairs. And we highly recommend stretching before you do any planking in the parks.

For some pointers, check out this civically-minded young man working his gluteus maximus in a city playground: