Sia is only getting more vibrant with age. Each release sees her stepping further away from her earlier downtempo work to a shinier, happier world where face paint and dance-pop rule. On the heels of working with Christina Aguilera on Bionic, Sia's more poised than ever for pop stardom. And you can tell she kind of knows it, covering Madonna's "Oh Father" and letting the dance beats bring out a quirky silliness that she's always kept bubbling just under the surface. But all that bouncy fun is underpinned by what remains one of Sia's best assets: her introspective lyrics.