Avril Lavigne August 31 at the Halifax Metro Centre. Thousands of girls singing “It’s a damn cold night” in their squeaky, pre-pubsecent voices, en masse, is an oddity you’d never hear in Halifax clubs. So the Metro Centre — alight with signature A. Lavigne glowsticks and $15 blinking devil horns — played host to the biggest, most expensive sleepover ever. Looking cheery and sounding surprisingly strong, Lavigne ripped through a breathless 75 minute set, dropping her hits among cuts from second album Under My Skin. She hit all the beats — girl power (“This one’s for all the girls!” she shrieked before launching into “Don’t Tell Me”), respect my musicianship (donning a guitar decorated like a Vans checkerboard sneaker, piano on two songs, stepping behind the kit for an encore cover of Blur’s “Song 2”) and capital-D depth (a solo, acoustic guitar version of homeless teen anthem “Nobody’s Home”). Banter was scarce, but three years on the road has certainly made a competent, if predictable, performer out of the once-sullen Ms. Lavigne. And, if you were sitting in the lower bowl, her engagement ring was big enough to cut your face.