Al Pacino,s upcoming movie-"Guys Stand Up"

Al Pacino.

Al Pacino, energized by a conversation that has inevitably turned to the intricacies of acting, is snapping his fingers.    

''When you get me on the acting trail, I get on that train,'' he says, punctuating what he calls an improvised ''thesis on time'' with staccato snaps.

The 72-year-old may be gray-haired and a little worn, but he remains, like a dancer, always on his toes, and still enamored of the ''crazy, crazy, crazy thing'' that is acting: ''You're always looking for what's going to feed you, what's going to feed the spirit and get you going.''

And Pacino is still getting going. Yet the subject of time, how much is needed to find a character (years in some cases, he says) and how it dictates the parts he chooses now, played a large role in a recent interview with the actor at the Waldorf Astoria in New York.

''Sometimes I'm tempted to say, 'Why am I doing this? Why am I still doing this?''' he says. ''Then, after I don't do it for a while, I say: 'Oh, now I know why I still do it.' If I suddenly didn't want to do it anymore, that'd be fine, too. I'd probably be an usher again in a playhouse.''

If Pacino is feeling reminiscent of his early days as a Bronx-born aspiring thespian knocking around in 1960s downtown New York theaters and cafes, it's partly because his recent work reflects on his beginnings. Not many know that Pacino started out as a comedian.

He jokes that though he did a movie with Robin Williams ("Insomnia''), ''he didn't know that I really wanted to be him.''

Pacino, funny guy, has certainly been glimpsed before. But after a career better known for gangsters, crooks and Shakespearean villains, Pacino has lately been exercising his comedy chops.

After finishing a revival run on Broadway of ''Glengarry Glen Ross'' in which he played up the laughs as the desperate, over-the-hill salesman Shelley, Pacino stars in the crime comedy ''Stand Up Guys,'' which Lionsgate will release Friday.

In it, he plays a former gangster, Val, released from prison after 28 years and taken around town to celebrate by his old friend, Doc (Christopher Walken), who does it remorsefully knowing that their boss wants Val killed by sunup. Their pal Richard (Alan Arkin) joins in the romp.

As he showed in ''Scent of a Woman,'' Al Pacino is good company for a last-hurrah. Part of his enduring appeal, after all, is his pulsating zest for life. Whether firing a machine gun at the hip ("Scarface''), pursuing a story ("The Insider'') or whipping a crowd into an ''Attica''-chanting protest ("Dog Day Afternoon''), Pacino is the great agitator of American movies.

Critics will make claims of over-acting, but no one ever slept through an Al Pacino performance.

''Some actors aren't connected and they don't invest,'' says ''Stand Up Guys'' director Fisher Stevens, a veteran New York actor and documentary producer.

''Al is committed to everything he does, even if it's just playing poker. He does everything that way.''

Stevens first met Pacino when he came to see him in a play two decades ago. It's the way many encounter Pacino; there are countless careers he's helped propel, from Kevin Spacey (whom he suggested for the 1992 film ''Glengarry Glen Ross'') to Jessica Chastain (whom he cast in his Los Angeles production of Oscar Wilde's ''Salome'').

Pacino made a film about the production, ''Wilde Salome,'' but it _ like Pacino's beloved, largely unseen ''The Local Stigmatic'' _ remains unreleased.

''That's what Al does with his movies, he just holds on to them like he's keeping his kids,'' says Stevens.

Pacino and Walken hadn't worked together before (except for separate scenes in, get ready for it, the Ben Affleck, Jennifer Lopez film ''Gigli''), but they've been friends for decades, going back to the Actors Studio, where the long-involved Pacino is currently co-president. Reading through the parts, the two decided to switch roles in ''Stand Up Guys.''

While Pacino's ''Godfather, Part II'' co-star and cinematic counterpart Robert De Niro has focused on comedy late in his career, Pacino has been more scattershot.

His most notable work in recent years was playing Shylock in an acclaimed 2010 production of ''The Merchant of Venice'' and an Emmy-winning turn as Dr. Jack Kevorkian in the HBO film ''You Don't Know Jack.''

(In March, Pacino will return to HBO in another high-profile biopic, this time on Phil Spector.)

His fondness for broad comedy, though, helps explain the most inscrutable credit in Pacino's filmography: the 2011 Adam Sandler film ''Jack and Jill,'' in which he, among other things, rapped a pseudo Dunkin' Donuts ad as ''Dunkaccino.''

''What happened to me is in life, I started to get used to other things besides myself doing something funny or coming up with jokes, and I started to get into what is the playwright and what the playwrights say and that the play is the thing, like Hamlet says,'' says Pacino.

''That's the reason I stayed in the profession because I fell in love with drama, whether it's comedy or tragedy."

EB