At one point in this endlessly, excruciatingly un-funny non-comedy, Dan (Robin Williams) and Charlie (John Travolta) are at a camp-out with Dan’s seven-year-old twins. Everyone agrees that it’s all about the kids. And of course there’s nothing more fun for kids than sitting on the sidelines while the grown-ups play all the games, right? So, we get to watch the kids watching the grown-ups. They have to look like they’re having fun. We, sitting there in the dark, do not have to pretend.

That’s about all the good news there is. Disney has doubled the same idea that worked surprisingly well in “Game Plan” — sports guy finds out that several years ago he became a father when the progeny get dumped on him for a visit and he has to learn how to be a father very quickly. It may have twice the fathers and twice the kids, but it has half the jokes and none of the heart. Instead of The Rock as a football player, we have Williams (the boring numbers guy who never does anything fun) and Travolta (the funny story-telling man who hits on women all the time) as long time best friends and business partners in a sports marketing firm who are (duh) just about to close the big, big deal when Vicki (Kelly Preston) shows up with the twins to explain that even though they were only married for one drunken night, she became pregnant and now that she is going to jail(!) for two weeks for trespassing in a protest against environmental damage, she needs him to take care of them. This is after the person she originally had to take care of them, her best friend the hand model (Rita Wilson), was hospitalized after Dan smashed her hands by closing a car trunk on them. Funny!

We then have a series of painful set-pieces featuring many members of the Travolta family (Preston is his wife, his daughter plays one of the twins, other members play extras) as Dan fails to be a good father and Charlie fails to be a good human. This happens being in many different locations, where they run into many different actors who all share a “how did I get here?” look. Matt Dillon and Justin Long show up at the camp ground. As soon as Dillon tells us how much he treasures his grandfather’s memorial statue, we know it won’t be around much longer. Dax Shepard and Luis Guzman are inept child-proofers. Guzman’s shtick is that he eats everything in the apartment! Un-hilarious! Amy Sederis flips out when Dan tries to bring the twins to the adults-only condo building! Un-comedic! Ann-Margret(!!) flips out when Charlie spoils a meeting of the bereavement group by eating the special pie made by a woman who died and by having a bad reaction to some medicine that gives him a grotesque facial rictus that makes him smile like the Joker! Plus many, crotch hits and poop jokes! And many jokes about how Dan and Charlie are mistaken for the kids’ grandfathers! And two separate episodes about the hallucinogenic and other bad side effects of the medications the men take for their age-related problems. Double plus un-good!

And I have not even mentioned how not funny it is when Dan’s son types a scatological term into the conference call with the big client, or when the same term comes up with reference to the bear scat Dan and Charlie wipe under their eyes before the game at the camp-out. Or how sad it is to see the wonderful Bernie Mac in the movie’s only bright spot as a children’s entertainer who helps out by giving Charlie a suit that will control every one of Dan’s movements to help him learn how to play tea party with his daughter. It reminds us how much we miss Bernie Mac. The rest of the time the movie just reminds us of how much we miss the days when Travolta and Williams were fun to watch. These old dogs need some new tricks.