NEW YORK (WABC) -- Whether you've used Citi Bike before or not, Friday's your chance to use the bike share program for free.In celebration of New York City's first-ever Car-Free Earth Day, Citi Bike will offer free rides on Friday to anyone who signs up for one online."This Car-Free Earth Day, we invite New Yorkers to 'Go Green by Going Blue'," said Jay Walder, President & CEO of Motivate, operator of the Citi Bike program. "Whether you've never been on a Citi Bike or you ride every day, Earth Day is a perfect time to strap on a helmet, get on a blue bike and gear up for the spring season. There are more reasons than ever to ride Citi Bike; this Earth Day we hope you give it a try."All you need to do is go on the Citi Bike website , enter your name and email address, and you'll get a code to redeem a free ride at any of the 470 bike stations around the city."We're excited to be sponsoring the Citi Bike initiative to go green this Earth Day," said Chris Reid, Executive Vice President at MasterCard, "Working with Citi Bike to not only enhance the consumer experience but also to demonstrate our support for environmental protection by promoting a car-free Earth Day is a true honor."