Insideschools' Going Green contributor Jennifer Freeman alerts us that February 23 is the last day for schools to sign up for the Green Cup Challenge.

Schools that join the challenge spend four weeks working to reduce electricity consumption in their buildings, tracking and comparing energy savings.

Last year the winner was PS 166 on the Upper West Side. The school saved $1,845  in electricity costs during the month from mid-January to mid-February. This year's challenge goes from March 4 to April 1.

Find out more about the initiative on the Department of Education's sustainability website.