By BRAD BARTH

There’s a reason it’s been 10 years since anyone last developed a Saturday Night Live sketch into a feature-length movie: Barring a few notable exceptions -- The Blues Brothers and Wayne’s World among them -- most of them have turned out to be major bombs.

But who better to defuse a bomb than MacGruber?

Actually, MacGruber is probably the last person you’d ever want disabling an explosive device, considering how frequently they blow up in his face. His eponymous movie, however, could wind up being a sleeper hit, despite a modest budget and accelerated shooting schedule that forced the film’s creative team to make the most out of everything they had -- much like our resourceful, yet easily distracted hero MacGruber. So how did they pull it off?

QUICK, VICKI! PASS ME A FULL-LENGTH PREMISE!

When SNL executive producer Lorne Michaels first suggested that MacGruber could stand on its own as a full-length feature, even MacGruber himself, Will Forte, had his doubts.  After all, said Forte, “It’s a 90-second sketch about a guy who blows up every time.” But once the film’s creative brain trust fleshed out the concept, the story possibilities seemed endless. And the jokes got more and more outrageous.

“No one ever stopped us,” said Forte, one of three co-writers who collaborated on the script.  “Every step of the way we kept thinking that somebody was going to come in and say, ‘Oh, you cannot do that; that’s crazy, that’s weird, that’s disgusting. That step never came.”

And that’s how they ended up with a scene in which MacGruber distracts several armed guards by running around naked with a celery stick inserted, ahem, where the sun don’t shine. Naturally, the day Forte shot this sequence, his mother decided to show up on set… with several friends. “I forgot that I should probably warn her about what was going on,” said Forte. “She couldn’t seem like she was okay with it in front of her friends, but I knew that she didn’t really care.”

Later in the film, co-star Ryan Phillippe, who plays MacGruber’s straight-laced sidekick Lt. Dixon Piper, would have to pull off the very same celery shenanigans. “I had to go to a really dark place,” admitted Phillippe. And so did the celery stick. (Rim shot, please.)

Mix in a healthy dose of MacGruber’s incompetence, some absurd action sequences, two disturbingly unsexy sex scenes and lots of stuff getting blown up, and you just might have a formula that causes people to explode… in laughter, that is. That goes for the audience as well as the actors.

Phillippe said that his primary job throughout filming was basically not to break into hysterics whenever Forte started goofing around.  “It was always an adventure,” he said. “I’ve developed a technique of stabbing my fingernail into my thumb to distract myself when I need to keep it together.”

SNL sensation Kristen Wiig, who plays Vicki St. Elmo in both the MacGruber sketches and the film, could barely hold it together during her bedroom scene with Forte. “You can see I turn my head a little bit because I’m actually laughing,” said Wiig. I don’t even know if they got one [take] where I wasn’t laughing. Sorry.”

OKAY!  NOW TOSS ME OVER SOME 1980s REFERENCES!

MacGruber is loaded with both obvious and subtle tributes to 1980s pop culture, which is always ripe for some good-natured parody. Obviously for starters, the film pays homage to Richard Dean Anderson’s MacGyver TV character. Both MacGruber and MacGyver seem to have an affinity for mullets and flannel shirts, and they both have an uncanny knack for, as the MacGruber theme song goes, “making life-saving inventions out of household materials!”

“All of us are huge fans of the original MacGyver series and obviously we found that inspirational for the initial [sketch],” said director and co-writer Jorma Taccone, who pitched the original MacGruber skit for SNL . But the film also draws inspiration from Die Hard, Lethal Weapon, Tango and Cash, Roadhouse, Uncommon Valor and pretty much every Stallone and Schwarzenegger film ever made. “The love runs deep for ’80s action movies,” Taccone added.

Keen-eyed moviegoers can spot references to some of these flicks in MacGruber’s geeky details. For instance, the bomb that MacGruber works on in the opening credit sequence is an exact replica of the C4 bomb in Die Hard. And the POV shot when Phillipe’s character is peering through his binoculars is a recreation of the binocular POV shot from Commando.

TEN SECONDS, MacGRUBER!

As of Friday, May 21, the countdown to MacGruber’s cinematic debut will have reached zero, and soon enough we’ll know if this latest SNL skit-turned-feature is just another bomb, or totally the bomb.

Either way, this probably won’t be the last SNL film to hit theaters, though one feature we can probably rule out is Gilly: The Movie, starring Wiig as everyone’s favorite classroom troublemaker.  “She only says, like, three things. That wouldn’t be a very interesting movie at all,” said Wiig. “And plus I would be playing a nine-year-old and I don’t think anyone really wants to see that.”

Oh yes, we almost forgot… there’s one last thing you should know about MacGruber before you go see it, and that’s the incredible surprise twist at the very end of the film. You see, what happens is --

BOOOOOOM!!!!! (MacGruber!)