By day, Venice is a city of museums and churches, packed with great art. Linger over lunch, trying to crack a crustacean with weird legs and antennae. At night, when the hordes of day-trippers have gone, another Venice appears. Dance across a floodlit square. Glide in a gondola through quiet canals while music echoes across the water. Pretend it's Carnevale time, don a mask - or just a fresh shirt - and become someone else for a night.