Some of today's hottest R&B; acts come to 1st Mariner Arena on Saturday, as R.Kelly, Ne-Yo, J. Holiday and Keyshia Cole take to the stage. Kelly's most recent album, Double Up, includes the singles "I'm a Flirt," "Rock Star" and "Same Girl." Cole exhibits a powerful, gritty style, which she showcased this summer when she performed at Artscape. The show starts at 7:30 p.m. The arena is at 201 W. Baltimore St. Tickets are $45-$100. Call 410-547-7328 or go to ticketmaster.com.