Next week is the MassRides Clean Air Challenge. You can participate by registering for NuRide at http://nuride.com/massrides and carpooling, vanpooling, taking public transportation, walking, biking or telecommuting to work. Track your green trips in NuRide during the week for chances to win prizes. You can also continue tracking your trips after the Clean Air Challenge is over and earn points at restaurants, retailers and attractions. Help keep the air clean by commuting green and saving some green!