HOLLYWOOD - Memorial Day weekend is typically one of the biggest for the box office, but this year's was more like a Hollywood buzz kill.

Fox's "Night at the Museum: Battle for the Smithsonian" got off to a solid start. Warner Bros. "Terminator Salvation" did not. Overall, ticket sales for the four-day weekend were up just 1.74 percent from a year ago, according to Hollywood.com box office.

"The box office definitely did not expand," said Dan Fellman, Warner Bros.' president of domestic distribution. "I don't think that's an indication we have to be concerned, but I think it's notable."

Box-office revenue through April was helped by a combination of big-budget event films scheduled earlier than usual, such as "Fast and Furious" and "Monsters vs. Aliens," and with smaller films that performed better than expected, including "Paul Blart: Mall Cop" and "Taken."

But since the summer movie season started May 1 with "X-Men Origins: Wolverine," the boom times have nearly evaporated. Box-office receipts through the end of April were up more than 17 percent. Since then, they have risen only 4.5 percent.

With the exception of "Star Trek," this year's summer event movies have performed worse than the ones that opened on the same date last year.

"Night at the Museum: Battle for the Smithsonian" and "Terminator Salvation" combined didn't even match the opening of "Indiana Jones and the Kingdom of the Crystal Skull" over Memorial Day last year.

"It was much easier to beat 2008 in the first quarter, but last summer was really strong and these comparisons are getting very tough," said Paul Dergarabedian, president of box office for Hollywood.com.

By any measure, however, "Terminator Salvation" had a relatively weak opening. The $200 million fourth installment in the 25-year-old sci-fi action series, financed by the Halcyon Co. and distributed by Warner Bros., grossed $53.8 million for the four-day weekend and $67.2 million since its opening Friday. Its $43 million gross Friday through Sunday is the softest for any big-budget action movie this year and even less than "Terminator 3" opened to in 2002, representing a significant drop when ticket price inflation is factored.

Although he said he was pleased with the opening, Fellman noted the "Salvation's" PG-13 rating, the first for a "Terminator" film, didn't draw young audiences. Only 14 percent of attendees were under 18.

"Night at the Museum: Battle for the Smithsonian" grossed a much more robust $70 million. The film got a less enthusiastic response internationally, where it launched in 93 foreign countries and grossed $50.1 million through Sunday. In many markets it placed No. 2 to the second weekend of "Angels and Demons," which has grossed nearly $200 million internationally in just 10 days.