ON THE TOWN: The Ringling Sisters (whose delightful "60-Watt Reality" album is just out) are holding their fifth annual Holiday Fund-Raiser for Needy Children Dec. 11 at the Roxy. Performers will include local faves Mary's Danish, the Havalinas, Steve Wynn, Henry Rollins, the Brothers Figaro and the Sisters themselves, with all proceeds going to an area orphanage. . . . Chris Poland (Megadeth's original guitarist) will be at the Whisky Tuesday. But we're wondering--is he promoting his new Enigma album, "Return to Metalopolis," or is he holding a showcase for A&R scouts interested in signing him if Enigma folds this month? . . . And a group of local actors and musicians (all contributors to the recent "Hollyword" compilation) will pay tribute to John Hammond, the late A&R exec extraordinaire , this Friday in "12x12," a night of music and spoken-word performances at the Highland Grounds. (Dec. 15 would've been Hammond's 80th birthday.) All proceeds from the show, which features 12 artists, including Linda Albertano, Harry E. Northup, Louie Lista and Danny (Shredder) Weizmann, will go to the John Hammond Fund at the Smithsonian Institution, which is preparing a concert series celebrating American roots music.