After giving the performance of her career in HBO’s Grey Gardens, Drew Barrymore tackles another killer challenge: directing. The empowerment theme of women’s roller derby suits her. Dialing herself back to the supporting role of Smashley Simpson, Barrymore focuses on Juno star Ellen Page as a teen Texas BBQ waitress who puts on skates to find her bliss. Bliss is her name, by the way, later changed to Babe Ruthless. Do you sense cutesiness sneaking in? It does, despite skilled actors such as Juliette Lewis as her rival and Kristen Wiig as a fellow Hurl Scout (cute again!). Screenwriter Shauna Cross dulls the edges of her novel Derby Girl, which the skate action and rockin’ soundtrack can’t disguise. At moments, especially in the conflicted intimacy between Marcia Gay Harden and Daniel Stern as Bliss’ parents, Barrymore shows real directing chops. But in Whip It she’s painting inside the box.