SFMOMA’s much anticipated birthday celebration on Friday night will include a dressed up ground floor and museum supporters in “attire to surprise” (which, though confusing, is still better than a recent nearby gala’s prompting for “cultural” dress). Brazilian Girls are set to perform after a rooftop dinner, and it will be a pleasure to celebrate 75 years of groundbreaking art, the Jeff Koons monkey/Michael Jackson sculpture notwithstanding.