When boy banders totter into middle-age, what do they do? Well, if you don't achieve solo fame a la Bobby Brown and Justin Timberlake, then you pretend you're still a horny teen, with a fan base of screaming girls. And you know what? Sometimes, inexplicably, you can still fill stadiums. Maybe even with a few gay boys in tow, in this case to cheer on NKOTB's recently outed (by Tiffany, no less) Jonathan Knight. They'll be loving you forever, it seems. They want it that way. Don't hold out for "The 2025 Walker Tour," catch them while they can still bust a pre-arthritic move. Friday, June 3, at 8 p.m. Verizon Center, 601 F St. NW. Call 202-628-3200 or visit verizoncenter.com. Tickets are $51.50 to $91.50.