With her sleek bob haircut (usually with a flower or two placed just so), vintage dresses, strikingly beautiful looks, and artfully customized ukulele, Janet Klein might seem at first to be a simple novelty act, a Generation X hipster ironically recreating the subtly naughty look of a fin-de-si+¿cle French postcard. Then she opens her mouth to sing. There's no Betty Boop hiccups or Mae West-style brassiness in her charmingly original voice. And when she starts to play the ukulele, it's clear that this oft-ridiculed cousin of the guitar is neither prop nor gimmick, but a deligh...