The Sundance hype and the fact that it's a very marketable film. It's got likable stars, great reviews so far, and it seems to be a "nice" film. For indie films, older people are often the target audience, and this is something that older people in socially liberal communities will eat up. I'm sure Focus Features is thinking of a Little Miss Sunshine type hit, and so they're spending the money to advertise it (with banners and such, and I'm seeing a bunch of TV and internet spots). So the hype is big and the per-screen-average will be giant, which is why your theater is smart to give two screens to it, and why you've got all them purty banners.