http://www.huffingtonpost.com/2013/03/16/chicago-river-green-st-pa_n_2891531.html?1363457260&utm_hp_ref=chicago
Updated story
A green Chicago River is the city-wide signal: the St. Patrick's Day festivities are officially on.
Saturday morning's event marked the 51st year of the river dying, a major part of the city's St. Patrick's Day Parade festivities.