One of the coolest things in Paris is the Velib bike rental system.   There 1,450 bike kiosks in town.  And each kiosk lets you check out a bike and return it to any other location.  The first 30 minutes are free, each 1/2 hour afterwards only costs 1 Euro.  

What a cool idea to get people out of their cars, which decreases both traffic and carbon emissions.  And it's a cheap, pleasant way of getting around town.  It's genius!