Universal execs are celebrating Mummy's Day a week early. The studio's action-packed pic The Mummy Returns — a sequel to 1999's The Mummy — grossed a record-busting $70.1 million over the weekend to rank as the biggest non-holiday opening in history. (Previous champ, Star Wars: Episode I &#150 The Phantom Menace, raked in $64.8 million in 1999.) Last week's top flick, Driven, slipped to No. 2 with $6.1 million, followed by Bridget Jones's Diary (No. 3 with $6 million), Spy Kids (No. 4 with $4 million) and Along Came a Spider (No. 5 with $3.8 million).