The domestic box office turnaround accelerated this weekend, with a record-setting Memorial Day frame largely thanks to “The Hangover Part II.”

The weekend was up roughly 10% over the holiday’s previous benchmark set in 2007, with Warner Bros.-Legenday Pictures’ drunken buddy pic scoring a whopping $137.4 million in its first five days and Paramount-DreamWorks Animation’s “Kung Fu Panda 2” contributing $68 million.

In total, four-day industry grosses are projected to come in at around $280 million vs. 2007’s $255 million benchmark, according to studio sources. (Both “Hangover II” and “Panda 2” launched on Thursday to benefit from a longer weekend, but opening-day grosses won’t go toward the weekend record.)

The holiday weekend was up about 49% over the same frame in 2010, marking the third straight year-over-year improvement.

Most B.O. pundits expect this trend to continue — important since year-to-date box office was off 11% vs. 2010 going into the weekend. Now, overall B.O. figures are down from last year about 7%.

“Just looking at the box office this weekend, you see that it’s starting to turn around,” said Warner distribution exec Dan Fellman. “And by mid-July box office should be up.”

Of its entire weekend gross, “Hangover II” collected $105.8 million from 3,615 locations since Friday for the all-time best comedy opening and Memorial Day weekend’s fourth-highest four-day bow ever, behind that of 2006’s “X-Men: The Last Stand” with $122.9 million. “Hangover II” added a stellar $19.7 million on Monday.

Par is estimating that its DreamWorks Animation toon “Kung Fu Panda 2” also had a healthy Memorial Day, tallying $14.4 million from 3,925 U.S. engagements.

Historically, Memorial Day has been a great day for moviegoing, particularly for family-friendly films, though “Hangover II” ultimately won the holiday as riotous momentum kicked up topnotch returns. (Studios based Monday estimates mainly on how comparable Memorial Day pics played that day.)

Fox Searchlight’s “The Tree of Life” did better than its earlier three-day estimates. The film, from River Road Entertainment, scored a per-screen average of $93,230 from four theaters vs. Sunday’s estimated $88,080 per screen, making it Fox Searchlight’s highest per-screen averge ever. Pic’s revised average brings it closer to the year’s best per-screen performer to date, Sony Pictures Classics’ “Midnight in Paris,” which averaged $99,834 from six debut locations last weekend.

“Tree,” which has a longer running time than “Midnight,” meaning fewer showings a day, debuted this weekend with a total four-day estimate of $488,920. “Midnight” grossed $2.6 million in four days from 58 locations, up from six last weekend.

“Hangover II” and “Panda 2” debuted internationally this weekend — the former was in 40 markets vs. 11 for “Panda 2” — and both far outpaced their predecessors in most debut territories.

“Hangover II,” which grossed $59 million (three times higher than the original), debuted with $16.7 million in the U.K., while “Panda 2” played tops in China and Russia, the later of which contributed $15 million, or 70% better than the opening for “Kung Fu Panda” in 2008. “Panda 2” earned $57 million this weekend from just 29% of the international market, based on Sunday’s estimates.

Disney’s “Pirates of the Caribbean: On Stranger Tides” again won the weekend internationally, posting $137.1 million through Monday for an overseas cume of $485.1 million.

The fourth “Pirates” pic is the year’s fastest-growing film at the global box office, as well as the year’s highest-grossing film so far. Pic crossed the $600 million global benchmark ($649.1 million) in just 12 days, matching the industry record set in 2007 by its predecessor “At World’s End.”

“Hangover II” and “Panda 2” were able to coexist this weekend as they did not target similar demographics. “Hangover II,” which skewed 54% under 25, had a relatively even split between men and women (the latter barely outnumbering men), while “Panda 2” played best to families, with 60%, and auds under 18.

Of the toon’s family aud, however, parents made up the majority, with 36% vs. 23% kid turnout. More parents — that is, more adult tickets sold — most likely meant that some families had to buy adult tickets for children over 13.

“Panda 2” earned 45% of its opening weekend gross from 2,707 3D locations — a lower-than-usual share even for family-driven films. But the toon didn’t screen at Stateside Imax theaters because of the company’s prior commitment to Disney’s “On Stranger Tides.”

DWA marketing topper Anne Globe said 3D “continues to be a strong storytelling technique for our filmmakers” before adding that “Panda 2” should expand to older teens (3D’s biggest supporters) over the next few weeks.

Toon received an overall A CinemaScore rating but played even better (A+) with auds under 18, who accounted for one-third of the toon’s opening weekend. “Hangover II” was given the same rating by under-18 auds, repping 13% of its opening, and an A- CinemaScore rating from all represented demos.

Fellman described Memorial Day weekend as traditionally a family-driven time at the box office, making the R-rated laffer’s record-setting perf even more impressive.

In another remarkable turn, Universal’s femme-driven raunchfest “Bridesmaids” dropped a scant 21% (based on three-day grosses), even with “Hangover II” in the market. “Bridesmaids,” in its third frame, took an estimated four-day total of $21 million, with an estimated domestic cume of $89.6 million through Monday.