Even longer than its predecessors, 3 piles on the series's usual comedy scenes and action sequences while adding some black slime from outer space and a few new actors (Thomas Haden Church, Topher Grace) to the more familiar faces (Tobey Maguire, Kirsten Dunst, James Franco, J.K. Simmons, Rosemary Harris). And a pile is what it feels like, especially when two superheroes ultimately join forces to defeat three supervillains. Given how bogus the movie is whenever it departs from formula, it's not surprising that the funniest bit (in which Peter Parker becomes a disco smoothie) is stolen from Jerry Lewis's The Nutty Professor or that the best special effects, involving a gigantic Sandman, dimly echo King Kong. Director Sam Raimi tries to pump some life into this dutiful enterprise but seems more than a little bored himself, especially when he's getting mushy about Spider-Man's moral decline and regeneration. PG-13, 140 min.