By Lisa Schwarzbaum
Updated January 20, 2013 at 01:09 PM EST
Credit: Thomas Kloss

Both have been famous since there were kids. Each is making smart, interesting career choices. And on the first full day of Sundance 2013, their latest projects aired back-to-back, making for an exceedingly satisfying Sundance-y day-into-night.

Credit: Thomas Kloss

Radcliffe plays Allen Ginsberg in Kill Your Darlings, and before you say, what, didn’t James Franco take care of that assignment pretty recently in Howl?, the answer is, this expressive, jazzy, ambitious movie by John Krakidas is something else entirely. In dramatizing a dark, hidden sidebar in the burnished history of Ginsberg and the Beat Generation – a murder entangling Ginsberg with William Burroughs, Jack Kerouac, their charismatic Columbia University muse Lucien Carr, and Carr’s obsessed admirer David Kammerer – the filmmaker explores the challenges both of artistic revolution as well as sexual honesty. The cast has turned over during the years Krokidas worked on it, but luck and fate have worked in the filmmaker’s favor: In addition to Radcliffe (who first expressed interest in 2008), Dane DeHaan is hot and dangerous as Carr, Ben Foster burrows into Burroughs, Jack Huston seduces as Jack Kerouac, and Michael C. Hall is just the right combo of desperate/creepy/lovelorn as Kammerer. The movie – stylish-looking on a shoestring budget – makes fab use of music, from “Lili Marlene” to TV On the Radio. And Radcliffe – hair permed into Ginsbergy college curls, full of vitality – holds the emotional center as a young artist in art and in life.

Meanwhile, in a sex tale of quite another color, Joseph Gordon Levitt writes, directs, and stars in Don Jon’s Addiction, an improbably entertaining and kind-hearted comedy about a specimen of New Jersey manhood – played by the filmmaker himself – who beds plenty of ladies, but gives his heart (and other parts) first and foremost to online porn.

Credit: Lewis Jacobs/NBC

Scarlett Johansson – comedienne! — channels a soupçon of Jersey gum-chewing doll and a dash of Judy Holliday to turn into the real-life girl of his (objectified) dreams who’s out to domesticate him; Julianne Moore is the earthy older woman (!) who teaches him what love’s got to do with it. Gordon Levitt goes broad in Joizy accent, in jokes based on stereotype, in sexual politics – but he does it with such good cheer that he leaves viewers with a happy ending.