The act used to be called “Hines, Hines, and Dad,” with papa playing a bit of drums but mostly beaming proudly as his sons engaged in the sort of strenuous tap dancing little seen since the jumping heyday of the Nicholas Brothers in the ’30s and ’40s. Though Gregory Hines is more often seen toting a gun on a movie screen these days, he’s been coaxed into bringing his fleet feet to town for the lecture series, “Give My Regards to Broadway.” While he’ll probably discuss his work in Eubie and Jelly’s Last Jam, one would like to see him do the Electric Slide. Can’t hurt to ask. Hines is joined by American University professor Carol Vaughn, founder of the Tap America Society, at 6 p.m. at the U.S. Department of Agriculture’s Jefferson Auditorium, 14th & Independence Ave. NW. $20-25. (202) 357-3030. (DN)