From sfcriticalmass.org: Critical Mass is a mass bicycle ride that takes place on the last Friday of each month in cities around the world. Everyone is invited! No one is in charge! Bring your bike!

Meet at Justin Herman Plaza at 5:30 p.m. More info sfcriticalmass.org. Some participants will be handing out this flyer at tonight’s event, urging good vibes.

Critical Mass website.

Critical Mass is a mass bicycle ride that takes place on the last Friday of each month in cities around the world. Everyone is invited! No one is in charge! Bring your bike! From Critical Mass

From SF Critical Mass Website: Critical Mass is a mass bicycle ride that takes place on the last Friday of each month in cities around the world. Everyone is invited! No one is in charge! Bring your bike!

From Critical Mass: Critical Mass is a mass bicycle ride that takes place on the last Friday of each month in cities around the world. Everyone is invited! No one is in charge! Bring your bike! Next San Francisco Critical Mass: April 26th, 2013, 5:30pm, at Justin Herman Plaza (foot of Market Street).