SUNDAY PM/MONDAY AM, 7TH UPDATE: Sources are giving me these North American box office numbers for this Presidents Day long weekend, not helped by wet weather on the West Coast or snow in the Midwest and Plains. The order has been changing since Friday and should keep changing right through Monday evening:

1. Unknown (Dark Castle/Warner Bros) NEW [3,043 Theaters]
Friday $6.7M, Saturday $8.8M, Estimated Sunday $6.3M
Three-Day Weekend $21.7M, Estimated Four-Day Holiday $25.6M

Liam Neeson’s latest action thriller was for Dark Castle/Warner Bros. PG-13 Unknown grabbed No. 1 Friday by overperforming and hasn’t let go yet. Leonard Goldberg brought the book to Joel Silver’s Dark Castle, which for once wound up financing a decently made film to decent reviews. “This could be the Dark Castle film Silver needs to shore up the DC financing and continue to make films under his DC label,” a Warner Bros exec tells me. Studio execs tell me Unknown was positioned as an interesting mystery with a newly popular hero to root for, as shown by early test screenings that proved the film had great playability. Trailers were placed on varied films to reach both younger & older audiences, from Hereafter to Unstoppable, True Grit to The Fighter, and even The King’s Speech. But TV was key, launching in early January with high-profile sports events and a strong mix of cable and prime time, again reaching younger and older audiences, both male and female. The hardest part of the marketing plan was how to protect the twists in the plot. The studio did that by keeping screenings to a minimum until opening week.

2. Gnomeo & Juliet 3D (Disney) Week 2 [3,014 Theaters]
Friday $4.3M, Saturday $8.4M, Estimated Sunday $6.3M
Three-Day Weekend $19.2M (-24%), Four-Day Holiday $24.8M, Cume $55.8M

I’ve been hearing since Friday that “the gnome movie” could end up No. 1 by Monday night. And, frankly, I didn’t believe it. But this holdover has become a real surprise. The toon ended up #5 Friday, but picked up steam thanks to weekend kiddie matinees as the only true family pic.

3. I Am Number Four (DreamWorks/Touchstone/Disney) NEW [3,154 Theaters]
Friday $6.2M, Saturday $7.6M, Estimated Sunday $5.4M
Three-Day Weekend $19.4M, Four-Day Holiday $22.6M

DreamWorks’ first feature release since it reconstituted itself at Disney debuted, and rival studios dumped on it all weekend in emails to me. I Am Number Four was neck-and-neck with Unknown all Friday. Then it started dropping. But the PG-13 sci-fi flick finished the three-day weekend #2 with a “B+” CinemaScore (“A-” under age 25) and underperformed from the high $20sM hoped for by the producers. I don’t know why DreamWorks debuted a pic with no stars, a derivative storyline, and a budget which it claims was under $60M with tax credits. I do think it’s still too early to pass judgment on much-in-demand Alex Pettyfer, who’s the new “It” young guy for so many roles including the upcoming CBS Films pic Beastly. Too bad director DJ Caruso couldn’t do for him what his Disturbia did for Shia LaBeouf’s film future. “We’ve got a well priced film with a new star that is for a targeted audience,” an upbeat Disney exec tells me. Meanwhile, the DreamWorks pic opened in eight territories this weekend, representing approximately 10% of the international marketplace.

4. Just Go With It (Sony) Week 2 [3,548 Theaters]
Friday $5.2M, Saturday $7.7M, Estimated Sunday $5.4M
Three-Day Weekend $18.2M (-40%), Four-Day Holiday $21.7M, Cume $64.2M

After winning last weekend’s box office derby, this Adam Sandler-Jennifer Aniston rom-com Just Go With It is showing legs. But why?

5. Big Mommas: Like Father, Like Son (New Regency/Fox) NEW [2,821 Theaters]
Friday $4.8M, Saturday $7M, Sunday $4.9M
Three-Day Weekend $16.2M, Four-Day Holiday $19M

Fox is just the distributor of New Regency’s $30M-budget threequel in its Martin Lawrence-in-a-fatsuit franchise Big Mommas: Like Father, Like Son which keeps dropping… Can someone explain why anyone goes to see this drivel?

6. Justin Bieber: Never Say Never 3D (Paramount) Week 2 [3,118 Theaters]
Friday $3.8M, Saturday $5.4M, Sunday $4.4M
Three-Day Weekend $13.3M (-55%), Four-Day Holiday $16.5M, Cume $51.3M

Bieber Fever was down nearly 70% Friday from Paramount’s Justin Bieber: Never Say Never 3D debut a week ago because these tween concert pics don’t really have legs. But then it leveled out. Doesn’t matter. The Canadian kid’s biopic only cost $13M and the studio expects it to gross over $60M for a nice chunk of change.

7. The Kings Speech (Weinstein Co) Week 13 [2,086 Theaters]
Friday $1.4M, Saturday $2.8M, Sunday $2.2M
Three-Day weekend $6.5M, Four-Day Holiday $7.9M, Cume $104.6M

8. The Roommate (Screen Gems/Sony) Week 3 [2,160 Theaters]
Friday $1.2M, Saturday $1.6M, Sunday $1.2M
Three-Day Weekend $4.1M, Four-Day Holiday $4.5M, Cume $33.1M

9. The Eagle (Focus Features) Week 2 [2,296 Theaters]
Friday $996K, Saturday $1.4M, Sunday $1.1M
Three-Day Weekend $3.6M, Four-Day Holiday $4.3M, Cume $15.7M

10. No Strings Attached (Paramount) Week 5 [1,966 Theaters]
Friday $900K, Saturday $1.2M, Sunday $1M
Three-Day Weekend $3M, Four-Day Holiday $3.7M, Cume $66.6M

For more estimates listed by title, see box office results here...

Editor-in-Chief Nikki Finke - tip her here.