Universal's family comedy The Flintstones In Viva Rock Vegas grossed $10.8m in its first three days at the box office over the weekend but was unable to beat U-571, also from Universal, in its second weekend. The submarine thriller grossed $12.3m, bringing its total to $38.2m after two weekends.

Viva Rock Vegas, a prequel to the 1994 blockbuster The Flintstones, is directed by Brian Levant and produced by Bruce Cohen, the team behind the first movie. It stars Mark Addy as Fred, Stephen Baldwin as Barney, Kirsten Johnson as Wilma and Jane Krachowski as Betty. Its opening paled beside the opening weekend take of the 1994 film which was $28m, but then again its budget was more modest.

Meanwhile New Line's well-reviewed Frequency, a time travel thriller starring Dennis Quaid and Jim Caviezel came in at number three with $9.1m. 20th Century Fox's Where The Heart Is was fourth with $8.3m. Where The Heart Is, a Wind Dancer production sold internationally by Intermedia, features Natalie Portman as a pregnant teenager who finds strength through a network of female friends (Stockard Channing and Ashley Judd among them).

The summer box office starts in earnest next weekend with the arrival in the marketplace of Ridley Scott's Gladiator which superlative test screening results and some massive advance buzz going for it. Expect a huge opening for DreamWorks SKG (Universal has international rights).

ESTIMATED TOP TEN US (APR 28-30)

Film (Distributor)/International distribution/Estimated weekend gross/Estimated total to date

1 (1) U-571 (Universal) Canal Plus/Summit Entertainment $12.3m $38.2m
2 (-) The Flintstones In Viva Rock Vegas (Universal) UIP $10.8m --
3 (-) Frequency (New Line) New Line International $9.1m --
4 (-) Where The Heart Is (20th Century Fox) Intermedia $8.3m --
5 (2) Love And Basketball (New Line) New Line International $5.5m $15.9m
6 (3) Rules Of Engagement (Paramount) Seven Arts International $4.8m $50.2m
7 (5) Keeping The Faith (Buena Vista) Spyglass $4.6m $25.7m
8 (4) 28 Days (Columbia) Columbia TriStar $3.8m $28.6m
9 (6) Erin Brockovich (Universal) Columbia TriStar $3.8m $113m
10 (10) Final Destination (New Line) New Line International $2.5m $46.1m