SUNDAY AM: Feel that heat? It’s another hot weekend at the box office, +40% over last year for $140 million in overall grosses. And it’s mostly due to the blistering North American performance of 3-D blockbuster Monsters vs Aliens. Despite so-so elite reviews, the pic totalled $58.2M this weekend, performing almost as huge as producer DreamWorks dared to hope, but better than distributor Paramount thought possible. (See below) It was the biggest pic of the year so far, and blasted through the record for a 3-D opening (held by Spy Kids 3-D) and RealD estimated it contributed  $25M of the gross. Also, 9% of the box office came from 143 IMAX screens. Monsters vs Aliens debuted to $16.8 million Friday and then soared to $24.3 million Saturday and an estimated $17 million Sunday thanks to crowded kiddie matinees in the widest release yet of a 3-D title — 4,104 theaters, including 1,550 3-D venues which had $3 to $4 premiums. This was almost the biggest non-sequel toon opening for DWA, behind 2008 summer hit Kung Fu Panda, but also one of the top non-sequel animation openings of all time. So 3-D is paying off for DWA chief Jeffrey Katzenberg (who’s constantly preaching about the technology’s superiority after pledging to make all future toons in 3-D).

As for Lionsgate’s The Haunting in Connecticut, it’s overperforming. The horror flicks’ late shows really picked up Friday night with $9.5 million Friday and $8.7 million Saturday and an estimated $4.7 million Sunday for a $23M debut weekend and 2nd place. As expected, the Fox-distributed WWE’s 12 Rounds starring John Cena was knocked out with a pathetic $5.3M opening weekend and #7. There also were strong holdovers:

1. Monsters vs Aliens (DWA/Par) OPENER, [4,104], Wkd $58.2M
2. Haunting in Connecticut (LG) OPENER [2,732], Wkd $23M
3. Knowing (Summit) Week 2 [3,337], Wkd $14.7M (-40%), Cume $46.2M
4. I Love You Man (Par) Week 2, [2,717], Wkd $12.6M, Cume $37M
5. Duplicity (Uni) Week 2, [2,579], Wkd $7.5M, Cume $25.6M
6. Witch Mountain (Dis) Week 3, [3,268], Wkd $5.6M, Cume $53.2M
7. 12 Rounds (WWE/Fox) OPENER, [2,331], Wkd $5.3M
8. Watchmen (WB) Week 4, [2,010], Wkd $2.7M, Cume $103.2M
9. Taken (Fox) Week 9, [1,961], Wkd $2.7M, Cume $137M
10. Last House (Rogue/Uni) Week 3 [2,251], Wkd $2.6M, Cume $28.4M

FRIDAY AM: This is certainly a rarity in the run-up to movie openings recently — a Hollywood studio that’s trying to raise expectations for how its film will perform. I’m told that distributor Paramount behind-the-scenes is trying to lower producer DreamWorks Animations’ forecast that its Monsters vs Aliens will do $60 million at this box office this weekend. (“You have no idea how many conversations we’ve had with them about how aggressive they are,” one Paramount exec told me.) The distributor thinks a more realistic number is around $50 million. It’s got the widest opening yet for a 3-D title. But even so, DWA’s Jeffrey Katzenberg and company still thought there’d be more 3-D screens up and running by now. But the economic crisis put a big dent in the theater chain and studio plans.

Also, it’s not summer. Kung Fu Panda set a non-sequel DWA record of $60M by opening in June. And with Jack Black starring, it played more like a non-family film. But Monsters vs Aliens doesn’t have a big celebrity draw beyond Reese Witherspoon (and her girl power is wobbly…) So most kids will be in school Friday instead of sitting in matinees. And Spring Break isn’t a factor because Easter is April 12th. So it’s $50M, not $60M — got it? UPDATE: Now rival studios are saying it’ll be $60M.

I haven’t seen a single TV ad for Lionsgate’s The Haunting In Connecticut, even though I do sneak peeks at Gossip Girl whose young female viewers are the target audience for these fright films. But I’m told Lionsgate was aggressive buying time during March Madness basketball. In any case, they must be out there because the horror pic is tracking better than last week’s Last House On The Left. Then again, Haunting is PG-13, and Last House was R-rated. Expect around $19M from 2,732 plays. And even my box office gurus were barely aware of the WWE/Fox’s 12 Rounds. Fox thinks it makes $7M-$8M from 2,331 theaters. Sorry, but John Cena ain’t no Rock/Dwayne Johnson.

The Top 5 should be:

1. Monsters vs Aliens (Dreamworks Animation/Paramount)
2. Haunting In Connecticut (lionsgate)
3. Knowing (Summit Entertainment)
4. I Love You, Man (DreamWorks/Paramount)
5. 12 Rounds (WWE/Fox)

Not only does Hollywood think Universal’s Duplicity will fall to 6th place, but Julia Roberts’ appeal has evaporated overseas where the pic is doing poorly, too.