For about the length of a good episode of television comedy, “Wanderlust’’ is really up to something. The jokes are smart and topical. The actors are on the same page about what is funny, and director David Wain, who wrote the script with Ken Marino, understands the comic effect of a well-assembled montage. This one traps Jennifer Aniston and Paul Rudd in a car. They are Linda and George, and when he loses his finance job and HBO rejects her penguin documentary, they leave their overpriced studio and drive to Atlanta to live with his obnoxious brother (Marino) and miserable wife (Michaela Watkins) but wind up entranced by a commune in north Georgia.

When Linda and George leave New York, it is like an exit from Eden. Their move south is an emotional pinball machine: laughing, crying, dueting, exasperation. You want to see what the movie might do with broke and homeless yuppies in New York. But that montage and the very funny scenes with Marino and Watkins and that first night on the commune promise a situation that could be just as fruitful. The fruit here hangs low, and it must be 35 years old. (Communes? Really?)

Linda and George move in with the hippies, and the movie turns as lazy, aimless, stoned, and stuck as the people living there. They include Justin Theroux, Alan Alda, Kathryn Hahn, Kerri Kenney-Silver, Jordan Peele, Malin Akerman, Joe Lo Truglio, and Lauren Ambrose, and everybody has a good moment with Aniston or Rudd.

But this movie has no teeth. It does not want to say anything, other than the unprintable word for penis, over and over. Once Rudd’s character loses interest in free love, male nudity, truth circles, and pot, it gives us permission to check out, too.