Not the post-Laurel and Hardy farce that the title might suggest, Pianomania is a fly-on-the-wall documentary about Stefan Knüpfer (right with Lang Lang, seated), an Austrian piano tuner (and Niles Crane lookalike) who tweaks the Steinways in Vienna's concert halls with the eagerness of an amateur mechanic, the nicety of a surgeon, and the semi-mystical sensory refinement of a master sommelier. There's a lot that the film doesn't tell us about Knüpfer's background, but it's a fascinating, slyly amusing peek into the classical music world, where "catastrophe" means a set of new hammer heads being 0.7mm too narrow.
Piranha 3D (18)
A lakeful of prehistoric piranhas make mincemeat of some holidaying students. Alexandre Aja's comedy horror doesn't aim high, and it's probably morally reprehensible, but there's a knowing intelligence behind it which makes it funnier than the competition. Richard Dreyfuss reprises his Jaws role, Christopher Lloyd does his goggle-eyed scientist bit from Back to the Future, Kelly Brook frolics naked underwater for minutes on end, and every imaginable severed body part floats towards the viewer in 3D.
Owen Wilson provides the voice of the eponymous Great Dane in this formulaic children's comedy. It may revolve around a surfing contest for dogs, and it may be preoccupied with bad puns and canine flatulence, but it still trots out Hollywood's two favourite pieties – "be yourself", and "don't prioritise your work over your family – or your pets" – for the billionth time. David Walliams must have been either relieved or disappointed when he heard that his role as a camp animal trainer was to be snipped to a 10-second montage.