"Primer" won the Grand Jury Prize at the 2004 Sundance Film Festival and has drawn repeat viewers eager to crack writer-director-star Shane Carruth's puzzler of a time-travel drama. Carruth, an engineer by training, plays inventor Aaron, whose entrepreneurial partnership with fellow brainiac Abe (David Sullivan) unexpectedly results in a process for traveling back several hours in time. The men initially use these rewind sessions to succeed in the stock market. But a dark consequence of their daily journeys eventually complicates matters. If this sounds like a very commercial, science fiction thriller, "Primer" is anything but that. Shot on 16mm for $7,000, the film has a tantalizing, sealed-in logic, akin to "Memento", that forces viewers to see the fantastic with a certain dispassion. One may be tempted to sit through "Primer" again to more fully understand its paradoxes and ethical quandaries. "--Tom Keogh"