The best midnight movies conjure a community experience, pleasing audiences who want to see reactions to the insanity onscreen. While many touchstones of the genre consist of notoriously strange and subversive visions that are primed for indie theaters — “The Rocky Horror Picture Show,” “The Room,” the works of David Lynch — the rise of home video, cable and, eventually, the darkest corners of the internet recontextualized fandom to include friends who want to introduce each other to increasingly odd stories, or simply work best after a bong hit or two. It’s risky to predict a future midnight movie classic, but the Canadian indie “ Buffet Infinity ” seems too strange to fail. Simon Glassman wrote and directed this feature-length story, which consists entirely of local advertisements from a small Alberta town that start normally, but things quickly feel … off .…