A Foggy Motion: There is more sluggish shuffling than dancing in Marathon33.33.

American Century Theater’s production of Marathon ’33 never gets any better than when you first walk in. The black box theater at Arlington’s Gunston Arts Center has been transformed into the Silver Slipper Ballroom, a venue that feels half middle-school dance, half county fair. In the far corner, a pretty decent jazz band (fronted by Ted Fuller) is warming up. Costumed ticket takers lead patrons to their seats while more than 30 actors roam the theater, some popping popcorn, others warming up for the dance marathon to come. A lanky older fellow wearing a medical coat asks patrons if they’ll be dancing. Play along by inquiring about your own medical conditions, and the “doctor” (Colin Davies), may slip you a Tic Tac. “It’s one of my special pills,” he said, prescribing a cure for my broken toe.

This exercise in improvisation and Americana is immensely amusing. But once the scripted interaction starts, the fun stops, and this two-and-half hour play about stubborn couples trying to win a Depression-era dance marathon turns into an excruciating test of patience. (I spotted newly empty seats after intermission.)

Marathon ’33 is an incredibly ambitious undertaking. The show was written in the late 1960s by June Havoc, but the name June Rose Lee might sound more familiar. Havoc was the younger sister of the Vaudeville-era stripper Gypsy Rose Lee, and Marathon ’33 picks up where Scene 10 of the musical Gypsy leaves off. Baby June, you may recall, escapes her show-biz mother’s clutches by eloping with another dancer in the family act. The marriage doesn’t last, and the opening of Havoc’s play finds Baby June starving and shoeless and auditioning for a dance marathon.

In the 1920s and 1930s, dance marathons set up shop across Middle America. Like traveling circuses, they entertained the masses while performers endured deplorable workplace conditions. Sidney Pollack depicted the phenomenon in his 1969 Academy Award-winning film, They Shoot Horses, Don’t They?

The movie was a compelling slow burner; the script of Marathon ’33 is an autobiography with an ax to grind. Jennifer Richter has a pathetically whiny role as June, who complains about Mama Rose in every scene. Bruce Alan Rauscher stars opposite her as Patsy, the veteran marathoner who claims her as his partner.

As depicted onstage, the marathon lasts for more than 100 days and involves very little dancing and lots of sluggish shuffling. The show’s most entertaining moments are fleeting dance scenes and character bits from the stronger female supporting actors. Several have good voices, which are made too sing far too many chestnuts from the American songbook. Reportedly, Kander and Ebb tried to talk Havoc into selling the rights to Marathon ’33 so they could revise it. She declined.

What a shame. Even in this problematic production, you can see the potential: Add character development, pacing, and audience participation, and Marathon ’33 could be as exciting as watching Usain Bolt win the 100 meters.

Well, maybe not, but you get the point. There’s a reason NBC only shows the marathon’s highlights.