Fashion and nightlife have long made merry bedfellows in New York City, and few have exemplified this union better than legendary event doyenne Susanne Bartsch, whose flamboyant style is celebrated in the exhibit “Fashion Underground: The World of Susanne Bartsch” at the Museum of FIT. The show highlights her dazzling, over-the-top party costumes as well as the British fashions she introduced to New York (in 1981 she opened a boutique in Soho where she championed emerging British designers like Vivienne Westwood and John Galliano). Bartsch’s decadent bashes, beginning in 1986 with a gathering at Savage, a club under the Chelsea Hotel, and continuing to the present with Kunst parties at Verboten in Williamsburg, have drawn haute fashionistas and downtown club kids decked out in outrageous attire for three decades.