There's a calypso-sunshine gloss radiating from the debut single by this week's MySpace sensation, but lurking beneath that bright surface is a wariness familiar to anyone who's spotted a Penn freshman on their first venture outside University City. "LDN" starts off as a simple tale of an afternoon bike ride—think the loose storytelling of The Streets' Mike Skinner packaged up in Nellie McKay's velvety singsong voice—then turns into a bemused travelogue of London's crack whores and grandma-muggers. Allen is only 20, so her lyrical naivete about her home city's underbelly is more charming than grating, and the midday-nap horn loop that "LDN" wraps itself around is so catchy that her lyrics breeze right by on first, second and seventh listen. In the end, "LDN" may be the quintessential pop song for the social-networking era; Allen's wide-eyed adorableness makes her a nice way to spice up your Top 8 for the day or two after you meet her, but once you start reading her blog regularly, you cringe for her a little.