Though he ranks among the finest comic minds of his generation, Bill Murray will be remembered more for his supporting roles (Tootsie, Ed Wood, Rushmore) than for his starring vehicles, in part because his sardonic wit carries a touch of arrogance that tends to keep him at arm's length. Murray's restless invention can elevate even the most slender material, and his dramatic range appears unlimited, yet unlike other leading men, he never invites easy sympathy or otherwise tries to ingratiate himself to the audience. No film has understood him better than Harold Ramis' brilliant Groundhog Day, a hilarious and unexpectedly profound comedy that breaks him down and reveals every conceivable facet of his personality. Like the high-concept equivalent of locking someone away until he's learned a lesson, Danny Rubin's original story forces Murray's character to exhaust his seemingly inexhaustible sarcasm and finally come to terms with its limitations. Murray stars as an embittered local TV weatherman who is sent to Punxsutawney, Pennsylvania, to cover the annual Groundhog Day festivitiesor, as he puts it, "the excitement of a large squirrel predicting the weather." After a surprise blizzard pens him in town with relentlessly optimistic producer Andie MacDowell and cameraman Chris Elliott, Murray wakes up the next morning to find that he's caught in a time warp, doomed to relive Feb. 2 in Punxsutawney over and over again. Groundhog Day comes up with wildly imaginative variations on the same encounters, mining new laughs out of Murray's mood swings and creative impulses and making the most of his talent for improvisation. In other hands, such a premise could have been under-imagined, but Ramis and Rubin consider all the possibilities and put Murray through a convincing progression. As he moves from denial to misanthropy to whimsy to depression, Murray learns so much about MacDowell and the town that he can plan his day down to the exact second. But the genius of Groundhog Day is that his calculations can only get him so far: He can plan a perfect day for MacDowellthe right drink, the right toast, a romantic dinner, a reading of 19th-century French poetrybut she ultimately picks up on his insincerity. For a Hollywood comedy, the film isn't afraid to lead its hero into surprisingly dark territory before he can climb his way out; Ramis doesn't go as far as, say, Paul Verhoeven might have, but what other PG-rated movie has ever included a montage of suicide attempts? The extras on the Groundhog Day DVD are nothing special, top-lined by an anemic commentary by Ramis and a half-hour documentary called "The Weight Of Time," but this edition does offer interesting insights into the difference between Rubin's original script and the finished film. Rubin's premise was decidedly artier: He began the story in the middle of Murray's time warp, so the audience would be immediately caught up in his disorientation. Ramis' decision to add straightforward character detail at the beginning speaks to his commercial instincts, but it also gives the journey a more meaningful arc. A throwback to a time when Hollywood films weren't so often cynical and insulting, Groundhog Day is a reminder of what popular entertainment can accomplish.