PARK CITY — History was made at Sundance’s kid-brother festival this past week. For the first time in Slamdance’s 11-year existence, eager movie watchers actually camped out overnight to buy tickets for the off-spin film event. And, yes, you guessed correctly: They were indeed “Lord of the Rings” fans. While addressing the sold-out audience before her movie’s world-premiere Friday at midnight, the director told the happy campers who braved the freezing Park City air, “I salute you.” Carlene Cordova’s documentary “Ringers: Lord of the Fans” spent the next couple of hours saluting J.R.R. Tolkien and the celebrated work he created 50 years ago — a phenomenon that has inspired hippies and cyber geeks, influenced artists in literature, movie and music industries, and entertained and entranced millions in multiple generations. [More]