Such defining efforts as Cocoon and Apollo 13 seem light years away for Ron Howard after his meanderings in the pages of Dan Brown (The Da Vinci Code and Angels & Demons) and this tripe about men behaving badly. Ronny and Nick (Vince Vaughn and Kevin James trading on their Swingers and King of Queens personas) are auto designers trying to secure a deal from Chrysler. Ronny's also just kicked a gambling habit, but his real trouble comes when he sees Nick's wife, Geneva (Winona Ryder, even more of a harridan than she was in Black Swan), getting friendly with a young stud (Channing Tatum). To tell or not to tell, that is the question posed by the title, but the "comedy" of miscommunication that ensues sputters and coughs more than one of Nick's malfunctioning muscle-car engines. Poor Jennifer Connelly gets wasted as Ronny's girlfriend, and Queen Latifah is squandered as an oversexed auto exec. Note to Vaughn: it's time to move on.