Do you know Old Gil from “The Simpsons” — Gil Gunderson, the shuffling, beaten-down salesman who never catches a break and doesn’t deserve one? (If you never watch “The Simpsons,” I say good day to you, sir; move along to “Ask Amy” on page E7.)

Dick Richards is a lot like Old Gil. He’s earthier, more full of himself, a bit profane and certainly slicker; that’s slick as in oil, snake oil. But Dick and Gil are cut from the same cloth, and that fabric shreds easily.

Dick Richards and his bumbling No. 2, Marggie Conway, would love to get you into a large boxy building that they are selling in the North Loop neighborhood of Minneapolis. That the building is the Lab Theater, and that the “For Sale” refers to the name of a new show from the Moving Company, is information we keep tucked away in suspended disbelief. Dick (Luverne Seifert) and Marggie (Sarah Agnew) are making a pitch — a big slow screwball of a pitch — to unload their real estate on us, the audience.

These characters are familiar — the frazzled and forgetful assistant, the grumbling and bumptious salesman. The joy of “For Sale” is just watching Seifert and Agnew rummage through these archetypes. What can I say? They’re funny. It doesn’t need to be more complicated than that.

Marggie gathers the audience on a landing area above the Lab Theater’s playing floor and promises us that her boss is on his way. Dick stumbles in, grousing about traffic and parking until he sees he has company. He switches on his unctuous charm and the two take us on a brief tour of an empty room (“This is a wall, made of Virginia brick. Over there is another wall, made of West Virginia brick.”).

Nathan Keepers, who wrote this script with Steven Epp and also gets credit for directing, shows up in the guise of several characters. The scenario twists in different directions, looking for some way to keep this farce afloat, but the air starts to come out of “For Sale.”

The actors work hard to regain their purpose and refill the comic drive and mission of the piece. And sporadically “For Sale” does rediscover its zest, but the initial promise does not sustain itself for 90 minutes.

By the conclusion, Dick Richards is thoroughly humiliated and defeated. He’s lost sight of the hope that he might unload this white elephant on one of us “turtleheads.” His life is in shambles.

“For Sale” makes a good case for its comic talent. Like Old Gil, though, it never quite closes the deal.