Big Brothers Big Sisters of Massachusetts Bay will hold its annual Big Night fund-raiser at the House of Blues Saturday, and this year’s special guests are Flo Rida and Nathaniel Rateliff & the Night Sweats. (Past performers have included the Black Crowes, Blondie, Hall & Oates, and Duran Duran.) Since 1998, the Big Night benefits have raised more than $30?million to support BBBS’s one-on-one mentoring programs. This year’s James J. Pallotta Award, given to someone whose support for at-risk kids has had significant impact in the community, is going to Josh and Anita Bekenstein.