Summer brings out the Bigfoot in Hollywood with blockbusters at the ready to stomp out any movie that values simplicity and sincere emotion. Well, don’t let summer squash Once, the Irish musical from writer-director John Carney that struck a lyrical chord at Sundance earlier this year. Cut through the Spidey-Shrek hype and seek it out. You won’t be sorry. It’s a magical, beguiling wonder. When I say Irish musical, think U2, not Riverdance, and get set for a gift of a movie that is absolutely worth seeing more than once. The Frames frontman Glen Hansard as a Dublin songwriter who takes his guitar to the streets and sings himself hoarse to deaf ears. That is, until he meets a pretty Czech pianist (Marketa Irglova) who gives him the guts to quit his dad’s repair shop and t finding the bucks to make a recording. That’s it, a bittersweet love story with ravishing Hansard music (“Falling Slowly” is a killer) and the ache of romance in its soul. Nothing about this mood piece should work — the budget is shoestring and the actors are inexperienced. But Once brims with small pleasures that pay major dividends. Carney, who played bass for the Frames till 1993, is a filmmaker to watch. Blending the hip and the heartfelt, the tough and the tender, he creates a movie you want to hold close.