Starting June 3, SFMOMA will be closed for almost three years as it expands its building to include neighboring parcels on Howard Street. About 600,000 people visit the museum every year, so the temporary shuttering will leave a big artistic void. As a way to soften the blow, SFMOMA is granting free admission — and free events — from Thursday, May 30, to Sunday, June 2, in what's essentially a four-day indoor Mardi Gras. Among the highlights: A roof party with live music and video projections on Thursday, starting at 6 p.m.; a 24-hour "Variety Show" of 20-minute sets — featuring the likes of comic Marga Gomez and drag performer Peaches Christ — from 6 p.m. Saturday to 5:45 p.m. Sunday; and a complete screening of Christian Marclay's 24-hour film, The Clock, from 10 a.m. Saturday to 5:45 p.m. Sunday. So, yes, SFMOMA is open all night (like a 7-Eleven) on Saturday, June 1. And SFMOMA docents and staff will be on hand the entire four days, giving talks on virtually every floor about their favorite art works. SFMOMA has been at its 151 Third St. location since 1995; this four-day sendoff is a chance to see the building before its 235,000-square-foot expansion. Expect larger-than-normal crowds, and crowds that are in the mood to get both wistful and raucous. It will be SFMOMA as you've never seen it before.