When proprietor Bashir Kahn first opened his tiny, windowless parlor-floor restaurant in 1990, he faced a challenge: With the adjacent block of Sixth Avenue already studded with Indian eateries, how could he stand out? His epiphany — that it was easier to achieve distinction with décor than with cuisine — was inspired. Khan subsequently transformed the boxlike space into a one-room Mardi Gras, festooning every inch of the foil-covered walls and ceiling with flashing colored Christmas lights, dangling illuminated chile peppers, mirrored balls, and sequined globes. Once he was done, there was hardly room for the dozen dining tables — but sure enough, patrons started filling them, if only for the hilarious experience of eating inside a Christmas tree. These days, the food still plays second fiddle to the ambience. Though the menu of Indian specialties is long, most choices are mediocre. Naan bread is too oily and dense, and banana fritters are overly sweet. Simpler, reasonably spiced entrées include sylhet shag (beef or chicken stewed with spinach in a piquant red curry sauce) and mild, yogurt-cooked lamb korma, redolent of cinnamon and cardamom.