One or two good acerbic jokes apart, Mean Girls isn't mean at all. It ends up as sentimental as any Hollywood suit could wish. Based on Rosalind Wiseman's bestseller, Queen Bees and Wannabes, it's a kind of Rough Guide to the peer-group pressures of American high school life - in particular, one Wannabe's triumph over a quite awful Queen Bee. Lindsay Lohan puts in a lively performance but doesn't get much of a chance as the Wannabe, back in America from Africa and thus ripe for tormenting; Rachel McAdams is the Bee.