The 2501 Residences on M Street — at 2501 M St. NW in the West End, two blocks from Georgetown — got to show itself off Sept. 21 with a reception for its million-dollar-and-up condos. The decades-old corner property once housed a medical association and, after a major reconstruction, now boasts more and even fancier digs — along with a Nobu restaurant, which provided the sushi. Arigatou.