The Revere Hotel tells us that it’s booked Susanne Bartsch to host a party and concert in its Space 57 on April 20, which is kind of a big deal if you’re a club kid. Bartsch is a famous New York party hostess and event producer who still runs big-deal club nights and recently threw a Valentine’s Day ball with “Sex and the City’’ stylist Patricia Field. This Boston event, which she’s calling “Bartschland in Boston,’’ will benefit the Institute of Contemporary Art. Performers on the roster for the night include JbDubs, a.k.a. James Whiteside, a former Boston Ballet dancer.