The summer box office is believed to have inched past the $4-billion mark over the weekend, thereby surpassing the record of $3.95 billion set in 2004. (Last year's total was $3.63 billion.) It occurred over a late-August weekend, which studios still consider a time when young moviegoers are preparing to return to school and have had their fill of expensive Hollywood productions. (In fact, the new record was attributed to higher ticket prices; the number of tickets sold was well below 2004's.) As it turned out, the studios dumped five relatively low-budget films into the megaplexes and none could beat the better holdovers. The one that performed the best was the one that few analysts held out much hope for. Rowan Atkinson's G-rated Mr. Bean's Holiday raked in $10.1 million in just 1,714 theaters. That works out to about $5,900 per theater, slightly less than the per-theater average of $6,100 taken in by the No. 1 film, Superbad, which grossed $18 million in 2,948 theaters in its second week. (The film, which has already taken in $189 million overseas, is now poised to cross over the $200-million worldwide mark early this week.) The fourth week of Universal's The Bourne Ultimatum placed second with $12.3 million in 3,679 theaters (the movie was also tops overseas with $14.4 million), while New Line's Rush Hour 3 finished in third place with $11.5 million in 3,442 theaters.