Ethan and Joel Coen's The Big Lebowski was released in 1998 to general bafflement. A decade on, it had become a cult classic and remains so over 20 years later, inspiring a thriving circuit of 'Lebowski Fests' during which costumed devotees gather at bowling alleys and guzzle White Russians. Beyond its superabundance of deliciously quotable lines, how has the movie inspired such remarkable affection? And why does its critical stock continue...