The narrative begins on election day in 2008, when Obama was elected president and California ratified Proposition 8. Lawyers immediately saw holes in this legislation, and over the next five years the case escalated through the courts, culminating in the Supreme Court decision in June 2013, repealing Prop 8. The film follows years of appeals, arguments, hearings, courtroom battles through the eyes of the plaintiffs, two same-sex couples who bravely volunteered to be the public face of equality.

This is one of the clearest depictions of why this isn't actually a religious or political issue. Events unfold with narrative momentum that's gripping, moving and often thrilling as we're drawn to these people in intensely personal ways. Both of the central couples (Kerry and Stier, Katami and Zarillo) are deeply likeable, and the unlikely legal team of Olson and Boies are priceless: they argued opposite sides before the Supreme Court over the Bush v Gore election in 2000.

Notably, Olson is a Republican who argues that marriage equality is a conservative value. His point is that the constitution has to protect people from those who are blind to justice. So it's no surprise that Olson faces a backlash from both his right-wing base and gay-rights groups who don't trust him. In other words, Olson single-handedly obliterated the partisan element of the case. When right-wing lawyer Charles Cooper argued that gay marriage causes harm, a judge asked him to define the harm, and he replied, "I don't know."

This simple, straightforward doc is lifted by its lucid exploration of how the US legal system dealt with a vital issue. Because it's told in such a personal way, it's riveting even though we know how it ends. It also touches on aspects of the issue that are rarely mentioned, such as how the word "traditional" is thrown around without true context or meaning. During this case, American history scholar Nancy Cott testified that "marriage has never been universally defined as a union of one man and one woman, and that religion has never had any bearing on the legality of a marriage".

What lingers is how this issue echoes a feeling all minorities know: from birth you're told that how you feel and who you are is wrong, which leaves you without dreams. All you can do is cope; you have no chance to find satisfaction, happiness or pride in who you are. Which frankly means that anyone who argues against equality is championing hatred.

Born in 1937 West Yorkshire, Hockney's earliest memories are of bombs falling and food rationing, but his father encouraged him to never worry what others thought of him. So he flourished as an artistic maverick. In swinging-60s London and art-boom New York, he developed his love of expressionism, then found his home in Los Angeles. "I was brought up in Hollywood and Bradford," he says, "because as a child I spend all my free time at the pictures." But the 80s and 90s were devastating, as he lost two-thirds of his friends and colleagues to Aids.

Hockney uses his work to reflect society, nature and his own journey, continually playing with time and space by bending perspectives and looking for new tools (he loves his iPhone's panorama feature). The film is packed with his observations, memories and, most tellingly, his feelings, which helps convey why his paintings resonate so strongly. There's also a fascinating parallel with the long life and career of Picasso, another representative expressionist whose paintings were overvalued during his life (Hockney hates this).

His friends trace each stage of his life, offering lively anecdotes about relationships, paintings and sexuality. The frankness is often very funny, but it's also revelatory when the filmmakers revisit people and locations from some of Hockney's most iconic paintings. Director Wright shoots and edits with a lush sensibility that's playfully indulgent. Yes, the movie goes on a bit, but it's packed with surprises, including snappy wit and strong emotional kicks.

Along with interviews, there's a terrific range film and TV clips, home movies and photos, plus an original score by John Harle that adds a sense of drama. The cumulative effect puts Hockney's paintings in the context of his life. And by pushing his own boundaries with forays into set design, using Polaroid pictures, fax machines, iPads and video installation, Hockney continues to find a bigger perspective. Indeed, his paintings open up around us, pull us in and force us to see the world through new eyes.

To be fair, Muhammad Ali is such a charismatic figure that it's not surprising that he won over almost everyone he met. From his early days as cocky upstart Cassius Clay to his activist years when he was banned from boxing for rejecting the Viet Nam draft, Ali was simply magic. Speaking to cameras or dancing around his competitors, he has always been true to himself while refusing to bend his principles. And the film shows that he was also a doting father and loyal friend as well.

Filmmaker Lewins assembles uses chapter titles like "A Daughter's Story" to introduce each new interviewee. This is the first hint that the filmmaker has herself become entranced by Ali, as she never steps back to get the bigger picture. She even retains comments about how looking into his eyes was like seeing God. These things might be true - his magnetic personality is undeniable in footage from throughout his career - but without a sense of perspective it begins to feel overstated and repetitive.

This also makes the film feel like a eulogy. Interviewees speak of him in the past tense, even though the 72-year-old Ali is still living with his wife in Arizona. But his Parkinson's is so advanced that he is no longer a part of their lives. Even so, their anecdotes are vivid and strikingly personal, mainly backstage things no one has heard before, including personal recollections from his brother Rahaman, ex-wife Veronica and children Maryum, Hana and Muhammad Jr.

The film slightly glosses over his four marriages and children from extramarital affairs, but it does include some of his controversial statements, including his shockingly brutal assessment of Joe Frazier before the "Thrilla in Manila", recounted frankly by Joe's son Marvis, complete with the apology and reconciliation. In other words, even if they have a bad word to say, it's tempered with something positive. The resounding positivity of this film is its only problem, because it makes Ali seem superhuman. But showing how a normal, flawed man could achieve such astounding feats and remain grounded is something all of us can aspire to.

Born in 1942, Ebert was a life-long newsman, working as a journalist before becoming the Chicago Sun-Times film critic in 1967. He hit the big time in 1975 when he began co-hosting the film review TV show Sneak Previews with his cross-town rival Gene Siskel, a prickly partnership that lasted until Siskel's sudden death in 1999. At age 50, he met his wife Chaz in an AA meeting, and she was his motivator through his 2002 cancer diagnosis and the loss of his speaking voice in 2006. But he kept writing right up to his death in 2013.

Ebert's reviews are distinctive for their personal touch, centring on his feelings about the films he watched. His encyclopaedic knowledge about cinema informed his opinions but never felt snooty. And he used his public influence to champion films that were off the radar of mainstream moviegoers. He was also a rare critic who was a close friend to filmmakers, including the likes of Scorsese, who credits Ebert with both his career and his sobriety.

The film is a snappy assembly of interviews, archival clips and photographs that tell Ebert's story with wit, warmth and energy. His lively sense of humour infuses the film, from a terrific outtake reel with Siskel to his perky conversations (by computer voice) from a hospital bed. His face may be disturbingly ravaged by this disease, but his eyes are always smiling, even as he insists that James records all of the most difficult details of his treatment.

This open approach is inspiring, although James struggles to balance these two elements of Ebert's life. It might have worked better either with a more chronological structure or even as a two-part doc, because this feels oddly unfocussed. For Ebert's fans, the sections centring on his review history are terrific (including clever clips overlaying his reviews with movie scenes), as are his comments on criticism itself. But the health-issue scenes tell us more about the man himself.