The question of whether to ditch a long-term friendship that no longer serves your interests is the wistful heart of “Nirvanna,” and is exponentially more interesting than the prankish publicity stunts that scaffold it. These include an admirably well-executed parachute jump from the observation deck of the CN Tower, enacted under the noses of security guards, and an elaborate time-travel plot that allows our heroes to reconnect with their 2008 selves. While much of this is muddled and repetitive, it is also now and then slyly amusing, as when the lads cross paths in 2008 with a string of now-infamous celebrities.