The Service Employees International Union (SEIU) local 1021 will attempt a Wisconsin-style occupation of San Francisco City Hall starting tonight and going well into tomorrow, May Day. Via the SEIU Facebook page, "We will take back city hall, Wisconsin style! This is IT. Arbitration begins Monday. We need to send a clear message to the Mayor and Board of Supervisors: Give us a fair contract!" SEIU, the city's most powerful public employee union, wants businesses "to pay more for the city services they enjoy, which workers hope would stave off pay cuts or increased health care payments," reports The Chronicle. Specifically, they're calling for Mayor Ed Lee's business tax proposal to pull in roughly $25 million to $40 million more than the $400 million the current business tax does each year.

Look for City Hall to be quite the spectacle. We're not sure when it will go down, exactly. But it will happen night. Tonight's occupation at City Hall prefaces tomorrow's May Day strike, which will bring ferry service to a halt tomorrow morning.