Picture taken from Creative Commons courtesy Flickr user Flowery 'L'u'z'a'

The annual free holiday parking rules is usually in effect from Thanksgiving through New Years Day, but its already started this year.  If there is a special cover on the meter, it means that particular parking space is free.  The holiday parking will be available in commercial districts including most of the downtown, parts of North Main Street and South Main Street, Wayland Square, parts of Atwells Avenue, Wickendon Street, Thayer Street, Broad Street and Olneyville Square.  However, cars parked illegally in cross walks, tow zones, or near fire hydrants will be ticketed.

Information from MetroSource.