It's all about capturing the attention of males 18-25, the most-coveted and easily distracted of all moviegoers. Or those who simply act like they are still 18-25 and can relate to these emotionally stunted comedy heroes.
"The hard R is directed at teenage boys of all ages," says Travers. "It says, 'This isn't going to be safe.' They push it to the limit."
Such as when Franco's dealer peddles his wares to grade-school kids or kicks Rosie Perez's dirty cop right where it counts. Or when Downey's pugilism-prone Aussie actor goes full-metal Method, resorting to blackface and a ghetto accent to portray an African-American soldier.
R Is for Riskier Funny Biz
Blame it on "Borat". "It opened up the door for films to again tackle political issues," Yale film professor Ron Gregg says of Sacha Baron Cohen's mock-doc assault on sacred cows, stereotypes and exposed body parts that collected $128.5 million in 2006.
"When Hollywood dealt with war directly last fall, it alienated audiences," he says. "Now comedies are starting to deal with national concerns outside of family and romance, like Sandler's You Don't Mess With the "Zohan" and "Harold & Kumar Escape From Guantanamo". We can laugh at the insanity."
Or as Todd Jackson, a humor writer who runs the comedy site Dead-Frog.com, says, "If you make people laugh and think, they like it. You can be smart about being stupid. People will let you get away with more."
While "Tropic Thunder" is more keen on taking well-aimed pot shots at the industry that feeds it rather than mocking the madness of war, "Pineapple Express" begins with a black-and-white prologue that subversively suggests none of the mayhem that follows would have happened if marijuana were legalized.
As shown by the poor reception to Myers' "The Love Guru" and Murphy's "Meet Dave", audiences aren't in the mood to play it safe. They require comedies with an edge, a sense of transgression. "My students talked endlessly about "Borat"," Gregg says. "They went to "Juno" over "Knocked Up". They are looking for novelty."
Making silly faces and doing a wacky accent is no longer enough. "Comedy used to be more about characters who were fish out of water or just weird," Jackson says. "Now they are dealing with the reality at hand, being more true to the situation."
Though their attitudes reflect unsettled times, "Pineapple Express" and "Tropic Thunder" had long gestation periods before reaching the screen. Stiller told ComingSoon.net earlier this year that he had the idea when he was shooting the Steven Spielberg epic "Empire of the Sun" in 1987.
"That's when all these Vietnam movies were being made," he said. "It was a time when all actors were going away to fake boot camp and talking about these incredible experiences that they had and how it really changed their lives. There was something there that seemed funny to me."
As for the over-the-top violence, including strewn guts and a bloody decapitation, Stiller felt he had to reflect the language and gore inherent in the movies he was satirizing. The thinking was, he said, "We should then at least have fun with it since we're going to have to be an R."
Meanwhile, "Pineapple Express" pays homage to the odd-couple action comedies of the '80s —"Midnight Run", "48 HRS", "Running Scared", "Beverly Hills Cop"— where raucous humor mingles with lethal gunplay.
But it was the Quentin Tarantino-scripted "True Romance" from 1993 that provided the inspiration for the story.