Perhaps the queen of the new bike sharing programs is Paris' Vlib bike rental program the name combines vlo (bicycle) and libert (freedom). It opened in the summer of 2007 and registered an astounding two million trips in its first 40 days. Twenty-thousand bikes are available at 1,450 cycling stations across the city. Insert a credit card to sign up ($1.50 a day to $43 a year) and you can drop your bike off at any other station, with the first 30 minutes free.Similar programs are sprouting up in big cities across Europe and North America. The first large-scale bike sharing system in the U.S. rolled out earlier this year in Washington, D.C., called SmartBike. Other cities with programs in place or at the planning stage are San Francisco, Houston, Tucson, San Antonio, Portland, Cambridge and Boulder. Chicago Mayor Richard Daley is reportedly a Vlib fan, so his city might become involved too. The large health insurer Humana tested a bike sharing program called Freewheelin for its employees in Louisville, Kentucky last summer and has since partnered with the not-for-profit Bikes Belong to take bike sharing to cities, corporate campuses and universities right across the U.S. Minneapolis/St. Paul and Denver were the first cities to sign on, with 1,000 bikes specifically for use at the Republican National Contention Minneapolis/St. Paul) and the Democratic National Convention (Denver). Following the convention, 70 "legacy" bikes each will remain, in the cities.