The power of a piano playing woman is quite remarkable. Fiona, Tori, Sarah even Nellie—they each have their own cult-like following, sustaining their careers through fights with labels, concept albums and ill-advised haircuts. Judging by Tuesday night’s performance, Regina Spektor can now officially be added to this list of keyboard icons. With the early 6 p.m. show, the 9:30 Club had the most popular happy hour in the city. The sold-out crowd cheered vigorously at…

MONDAY >> If you’re not high-tailing it to the Maryland end of the Orange line to see the Redskins take on the Vikings, you may want to pay the Black Cat’s backstage a visit to see The Whigs. This trio from Athens, GA has been called the “best unsigned band in America” by Rolling Stone. $8, 9 p.m. >> The haunting, violin-driven alt country of the Black Swans is coming our way. Catch these boys…