Grand Jury Prize-winner at Sundance 2004, Primer is a geeky little no-budget number about two suburban family guys who bash together a weird machine in their shed. They use spooky pipes, remixed circuitry and... that stuff that makes fridges work. Eventually, it looks like an unholy hybrid of an Apple PowerMac and the 2001 obelisk. When they turn it on, it makes a really odd noise. Oh, and it slows down time... Writer/director/composer Shane Carruth presents the story as one of cold, consuming obsession. Back To The Future it ain't. Unless you're an engineering PhD, there's no easy way into the two men's conspirational world of dense, overlapping jargon. It's like straining to tune into a conversation where it's clear something extraordinary is being discussed, if only you could work out what. Watch it three times. First time round, you'll be baffled and irritated. Second time, there'll be a few "Aaah! Now I see!" moments. Third time, it's as if David Lynch had directed Memento.