Sex sells. That's a maxim more commonly applied to glitzy Hollywood films than independent ones, but it is true even at the Sundance film festival, where audiences bundled up for the Utah winter have over the past 10 days been flocking to see famous people remove their clothes. This year's festival has boasted a bumper crop of onscreen flesh of all kinds, from straight porn addicts to gay leather bars to foxy moms sleeping with each other's sons to a lesbian who suffers a concussion and decides to become an escort.

All of this smut has got people talking. Local conservative groups in Utah made empty threats about boycotting the festival. The talent agency CAA threw an instantly infamous party featuring burlesque dancers on poles. Even Sundance veterans have been making cracks about "Porndance" and wondering how the festival suddenly became so racy. Sundance has always been known for pushing boundaries – Steven Soderbergh and the festival were both put on the map when sex, lies and videotape premiered here in 1989, and it's long been a cliche for Hollywood actors to try to change their images by signing up for an indie film and taking off their clothes.

But the festival's biggest successes in recent years have generally had more on their mind than titillation, with dramas like Precious or Beasts of the Southern Wild tackling tough social issues, or hardheaded documentaries from the likes of Michael Moore and Al Gore turning the world's attention to problems it might rather ignore.

Of course, sex comes with its own problems as well. James Franco, who brought unsimulated and graphic gay sex to this year's festival with his experimental Interior: Leather Bar, also appears in the biopic Lovelace as none other than Hugh Hefner, one of the many men called out for taking advantage of famous porn actress Linda Lovelace (played by a nearly unrecognisable Amanda Seyfried). As if one porn biopic wasn't enough, there's also Michael Winterbottom's The Look of Love, which stars Steve Coogan as the legendary "King of Soho" Paul Raymond, and offers plenty of nudity and depravity, possibly to cover up what some critics called lifeless and dull storytelling.

Back in the present day, porn is also a major factor in Don Jon's Addiction, the writing and directing debut of The Dark Knight Rises boy wonder Joseph Gordon-Levitt, who also stars as a musclebound New Jersey dude proud of his crippling porn addiction. Gordon-Levitt is embodying some of that familiar high-minded Sundance spirit, trying to explore the way modern access to porn warps the brains of young men, but that idea is masked pretty well behind a whole lot of sex scenes and jokes. Unsurprisingly, Don Jon's Addiction sold very well.

Then there's Two Mothers, an unintentionally funny drama in which Naomi Watts and Robin Wright sleep with each other's teenage son. And Stoker, in which Mia Wasikowska plays a teenager whose sexual awakening is linked inextricably to violence. The most talked about sex scene of all last week probably involves Daniel Radcliffe, who in Kill Your Darlings plays famous Beat poet Allen Ginsberg as he comes to terms with his homosexuality. The promise of Harry Potter's gay kiss may get people into Kill Your Darlings, but it's also an insightful look at the poet's life with a great performance to boot – an example of how, at Sundance, some of the sex they are selling comes with deeper meaning too.

Of course, many of this year's biggest hits don't fit this trend at all. The dramas Fruitvale and Blue Caprice make up their own mini-theme of harrowing true-life stories acted out on film, recreating the shooting death of a 22-year-old black man in San Francisco and the 2002 Washington DC sniper respectively.

The biggest sale of the festival has been The Way, Way Back, a light comedy so reminiscent of Little Miss Sunshine it even shares part of its cast, with Steve Carell and Toni Collette in two lead roles. It sold for $10m, the kind of sky-high price not seen here for a few years. There's been no single runaway hit in 2013, although at the time of writing Fruitvale and The Spectacular Now were being widely tipped for the audience award. The festival may have had its mind in the gutter this year, but in the hands of some of these film-makers, it was an interesting place to be. Here are some of the highlights.

THE WAY, WAY BACK

Director Nat Faxon and Jim Rash
Cast Steve Carell, Toni Collette, Allison Janney, Sam Rockwell, Liam James
What's it about? After winning the Oscar for co-writing The Descendants with Alexander Payne, Faxon and Rash make their directing debut with a coming-of-age story about a 14-year-old boy on vacation with his mom (Colette) and her overbearing new boyfriend (Carell). He finds solace by taking a job at a local water park, and also in a fledgling romance with a neighbour.
Did it sell? Fox Searchlight picked it up with a sky-high $10m offer, and is planning a summer release – New York Post

KILL YOUR DARLINGS

Director Jon Krokidas
Cast Daniel Radcliffe, Dane DeHaan, Ben Foster, Jack Huston
What's it about? Before Allen Ginsberg (Radcliffe) was a legendary poet, he was a sexually confused freshman at New York's Columbia University, developing an intense friendship with the charismatic Lucien Carr (DeHaan), who introduces him to fellow Beat legends Jack Kerouac and William S Burroughs. But the burgeoning literary movement the four men dream of hits major trouble when all four of them are implicated in a murder.
Did it sell? Sony Pictures Classics picked up the rights for the US and several other English-speaking countries, though not the UK.
What the critics said "Kill Your Darlings succeeds more than most in capturing the first flickers of the literary movement without hipster self-consciousness" – Hollywood Reporter

THE EAST

Director Zal Batmanglij
Cast Brit Marling, Ellen Page, Alexander Skarsgård, Patricia Clarkson
What's it about? Co-writers Batmanglij and Marling debuted at Sundance two years ago with Sound of My Voice, about undercover journalists investigating a cult. They return with another story about a tight-knit group being infiltrated by an outsider, this time the violent environmentalist group the East, led by a charismatic Skarsgård, and the infiltrator is Marling, a corporate spy hired to keep the East away from her company's clients.
Did it sell? Already had a distributor – Fox Searchlight – which brought the film to the festival.
What the critics said "[A] clever, involving spy drama build[ing] to a terrific level of intrigue before losing some steam in its second half" – Variety

STOKER

Director Park Chan-wook
Cast Nicole Kidman, Matthew Goode, Mia Wasikowska, Jacki Weaver
What's it about? The English-language directing debut of Korean auteur Park, renowned for 2003's hyper-violent Oldboy, Stoker is a riff on a gothic melodrama that brings Goode's Uncle Charlie back into the family fold after the mysterious death of his brother. His relationship with his niece India (Wasikowska) starts off a little creepier, but only gets wilder, more lurid and more violent from there.
Did it sell? Didn't have to. Another Fox Searchlight picture, with a US release set for 1 March.
What the critics said "A splendidly demented gumbo of Hitchcock thriller, American Gothic fairy tale and a contemporary kink all Park's own" – Variety

THE SPECTACULAR NOW

Director James Ponsoldt
Cast Shailene Woodley, Miles Teller, Kyle Chandler, Jennifer Jason Leigh
What's it about? Returning to Sundance just a year after debuting his acclaimed drama Smashed, Ponsoldt adapts Tim Tharp's young adult novel about a popular high school senior (Teller) who falls for a shy classmate (Woodley, from The Descendants). Far from a typical high school couple, the two grapple with his drinking problems, her lack of ambition, and strained relationships with their parents, all with a sharp mix of humour and drama.
Did it sell? Upstart distributor A24 picked it up just a few days after the premiere, and plans a summer release in the US.
What the critics said "… benefits from an exceptional feel for its main characters on the parts of the director and lead actors" – Hollywood Reporter

BEFORE MIDNIGHT

Director Richard Linklater
Cast Julie Delpy, Ethan Hawke
What's it about? Nine years after reuniting in Before Sunset, and 18 years after meeting on that train to Vienna in Before Sunrise, Celine and Jesse are once again together and talking in Europe, this time in southern Greece. Fans of the trilogy may be anxious to know what has happened to the famous pair of lovers, but we wouldn't dream of spoiling it…
Did it sell? Yes, to Sony Pictures Classics for a rumoured seven-figure sum.
What the critics said "A complicated, meandering but also wonderful film" – Screen Daily