01/21/2013 09:05 am ET Updated Mar 23, 2013

Live from Sundance 2013: Sunday, Jan. 20

I had a four-movie day Sunday at the 2013 Sundance Film Festival and still felt a little like I was slacking off.

Maybe it's that I had time to kill between films. Maybe it's that I enjoyed these films more than most of the ones I saw on Saturday.

And it's not as if everything I saw on Sunday was a gem. Only a couple of them were.

The most intriguing film of the day was Concussion, a film by Stacie Passon that could be considered a Sapphic version of Belle de Jour. Except, in this case, the wife, Abby (a marvelous Robin Weigert), isn't frigid; instead, she's unsatisfied in her marriage to lawyer Kate (Julie Fain Lawrence). But it takes a bonk on the noggin -- a ball thrown by one of their children - to rattle that need loose from where she was keeping it locked away.

Before long, she's set herself up as Eleanor, sexual guide for other women who may have needs their husbands can't fill and the curiosity or long-gestating urge to look elsewhere: "You're like a hot dyke housewife," she's told, as a way of how to sell herself to a discreet clientele. She quietly and secretly begins to see clients at a loft she's been rehabbing in Manhattan, even as she seems to be happily living the married life in suburban New Jersey.

Weigert gives a subtle, moving performance as a woman who finally takes control of her own needs and makes a number of discoveries about herself. It's a quiet, controlled and compelling film, one that could conceivably make a star out of the warm yet self-protecting Weigert.

I also liked A Teacher, a shorter (75 minutes) feature in the festival's Next section, directed by newcomer Hannah Fidell. Lindsay Burdge plays Diana, a Dallas high school teacher who is having an affair with one of her students, Eric (Will Brittain). Things are fine until she gets spooked at a close call when they almost get caught. When Eric waves it off as not as big a deal as she thinks, she begins to have second thoughts about the affair she enjoys so much. But when she breaks it off with him, she has second thoughts about that as well -- and second-guessing becomes her downfall.

Though compact and self-assured in its telling, "A Teacher" generates a lot of tension -- and then an amazing sense of doom as Diana makes one misstep after another, after obviously being a skilled player up to that point. Fidell never judges Diana; indeed, she and Burdge make her seem both brave and daring, seeking her own happiness (though what she's doing is obviously illegal). The movie a tight little ball of stress, handled with deftness by Fidell.

This commentary continues on my website.