A few blocks from Grand Central Station in Midtown East, Uncle Charlie’s is in a part of town known more for its office buildings than its nightlife. That has worked in the piano bar and lounge’s favor: In its four years it has become a hugely popular after-work spot among the area’s flourishing gay white-collar scene. Two-for-one drinks during happy hour, nightly drink specials and captivating entertainment keep the guys around all night long. Located...