Four thousand film festivals populate the globe. But more than many, the San Francisco International Film Festival may satisfy a collective hunch of what such a gathering should be. Perhaps age has something to do with it; at 53 years old, SFIFF, held this year from April 22 to May 6, 2010, is the oldest film festival in the Americas.

Then there's the topography of San Francisco, which rises, falls and yields vistas that themselves cop filmic metaphors. Or maybe it's because San Francisco natives form a cultured urban tribe. And if not all that, then its timing — following the previous year's key festivals and preceding mighty Cannes — is enough to drive any fest into compensation mode. Graham Leggatt's four years as head of the San Francisco Film Society have spread the enterprise's sticky tentacles in ambitious and effective ways.

Whatever the reason, the Festival styles itself with distinctive flair for its 80,000 or so annual attendees. This year's spin will set in motion some 150 films and live events. By Festival's end, it will have pinned more than 20 ribbons on industry worthies.

Don't you wish you'd been a fly on the wall when the SF Film Society chose John Waters as the man to present Ang Lee's writing partner, James Schamus, with the 2010 Kanbar Award for screenwriting? The transgressive cult director and the Focus Features honcho make one odd couple. By all appearances, the Society's sense of humor has survived the lumpy economy intact.

Walter Murch is its pick for this year's trippy address about "cinema and visual arts, culture and society, images and ideas." The film editor, sound designer and nine-time Oscar–nominee will retell cinema's genesis from the 19th century to now, and dip into the legacies of Beethoven, Flaubert and Edison. Asked to play prophet as well, Murch will foretell how cinema's formative milieu will beget future audiovisual expression.

Such inspired vapors should hover over the Sundance Kabuki Cinemas when Walter Salles receives the 2010 Founder’s Directing Award. For his tribute, an hour-long preview of In Search of On the Road will be screened alongside his other clips. Specially cut for the Festival, this work-in-progress chronicles Salles's efforts to shoot a documentary about Jack Kerouac, his seminal road-trip novel On the Road and the post-war artists, poets and pharmaceutical enthusiasts of the Beat Generation.

In another mix of the vintage and the new, SFIFF will once again screen a silent film to the live accompaniment of an original score by a contemporary musician. This year's pairing is Stephin Merritt and his newly unveiled score for the 1916 epic 20,000 Leagues Under the Sea. The event will take place at the landmark Castro Theatre.

A whiff of the quaint surrounds "An Evening with Roger Ebert and Friends," when directors Jason Reitman, Terry Zwigoff and others will gather at the Castro to give the well-known film critic the Mel Novikoff Award. Named for San Francisco's pioneer art-house exhibitor, the award honors those who have made significant contributions to Bay Area filmmaking.

An especially hot ticket is the Midnight Awards, a cocktail toasting an American actor and actress. Taking the cue from late-night talk shows, the witching-hour event features a confab with the two and a sampling of their work. Live music will be performed by Marc and the Casuals.

Each year the Festival heralds an up-and-coming talent via a "Centerpiece" screening of his or her work. The 2010 choice is Josh Radnor and his directorial debut, happythankyoumoreplease. Zoey Kazan, Malin Ackerman and Pablo Schreiber are among the ensemble joining him in front of the camera, where he plays a struggling writer in this Manhattan tableau of Gen Y in post 9/11 Manhattan. Radnor, who also wrote the screenplay, is expected to attend the Kabuki Sundance screening and Centerpiece party at Manor West.

This year's Peter J. Owens Award goes to Robert Duvall at an event featuring an interview with the actor and a look back on his half-century of performing in such standouts as The Godfather, Apocalypse Now, The Great Santini and Tender Mercies, for which he took the Best Actor Oscar. Also screening will be Aaron Schneider's Get Low, in which Duvall plays a pariah from the Tennessee sticks who opts to put on his own funeral while still breathing.

Don Hertzfeld, one of a handful of animators who produces all aspects of his films, is slated to take the Persistence of Vision Award. The Academy Award–nominated shorts filmmaker will be on hand during a rewinding of his career, including such popular titles as I am so proud of you and Intermission in the Third  Dimension.

SFIFF's roster of trophies — which culminates with the Golden Gate Awards — unfolds alongside a vigorous regime of partying. Following the Opening Night film, Micmacs, celebrations will carry on amid the Beaux Arts architecture of the Regency Center. The Closing Night party will feature music inspired by the brash comedian Joan Rivers, who is the subject of Ricki Stern and Annie Sundberg's documentary, A Piece of Work, which will be screened during the Festival.

Students of the human comedy will have a chance to see Hirokazu Koreeda's newest work, Air Doll. The conceit is flippy, or at least Mannequin-esque: an inflatable "love doll" comes to life and falls in love in present-day Tokyo. Billed as an "anti-fairytale," this meditation on love and loneliness stars Korean leading light Bae Doo-na.

Sri Lankan filmmaker Vimukthi Jayasundara returns to San Francisco, following his 2008 film, The Forsaken Land, with Between Two Worlds. His new drama about the scars of his country's 20-year civil war will screen in the New Directors category.

Civil war, or at least its gathering clouds, also informs White Material. Claire Denis' somber tale of a French matriarch (Isabelle Huppert) who insists on weathering Africa's political chop marks the director's first film situated in that continent since Beau Travail. White Material will be screened under the World Cinema rubric, as will Around a Small Mountain, by her fellow French auteur, Jacques Rivette. Erring on the lighter side, his newest film follows the love story between a French circus performer and an Italian quester who hopes she'll trapeze over her fears.

The full lowdown on San Francisco's two-week cinema circus is posted at www.sffs.org.