Let's see. An A-list film based on a wildly successful musical based on campy, cult-beloved original material. Where have we heard that before? Mamma Mia sure seems to be a variation on the Hairspray formula. Just add Meryl Streep, shake and spray! And sure, nothing here compares to the kitschy joie de vivre of ABBA's original tunes (or the stage version, for that matter), but there are a few pleasant surprises here: Big Love ingenue Amanda Seyfried has a nice voice. The always fabulous Christine Baranski is, naturally, fabulous. And Streep sings a mean "Dancing Queen."