When this little Tremont bar opened in 1999, it did so with five tables, four lava lamps, three red-lit ceiling fixtures, two 1950s-style sectional sofas, and a single multitasking bartender who took orders, fixed drinks, served food, and brewed coffee. Since then, the Lava Lounge has come of age. The addition of a handsome upstairs dining area has more than doubled the seating space. Silver-topped tables and candlelight make the atmosphere less shabby than chic. And the formerly handwritten menu has morphed into a well-organized listing of mix 'n' match "small plates" ranging from oysters on the half shell to empañadas, egg rolls, and an astonishingly delicious rib-eye sandwich. What hasn't changed is the moody vibe and the late-night hours, with entertainment beginning at 10 nightly (including live jazz on Mondays) and the kitchen mixin' it up until 2 a.m. Get down to the Lounge, and you'll never be lonely again.