On the HBO series Entourage (Sundays at 10), Turtle (Jerry Ferrara) is Harpo, the least assimilated of the three pals who hang on young movie star Vince (Adrien Grenier). He speaks, all right, but he’s unapologetically old country (Queens) in his dress (ghetto track rig all the way), appetites, and attitudes. When one of the other boys (and they are boys, make no mistake) laments that the only reason a woman he’s interested in would be willing to sleep with him is because of his relationship to Vince, Turtle, pure id, is incredulous: “What’s wrong with that?”

The third season finds the Entourage entourage continuing their pursuit of sex and toys — Vince’s big house, the fancy cars, the girls. Vince has worked his “authentic” NYC street cred and dark ethnic good looks to trade up to a James Cameron vehicle, Aquaman. (Cameron is one of many Hollywood types who make cameos as themselves.) Vince is the one character who seems able to straddle both worlds — a fully socialized, sensitive guy, unashamed of his roots, vulnerable to love (Mandy Moore as herself last season). But the blockbuster-action-movie role could make him just another white boy.

Vince’s older brother Johnny (Kevin Dillon) justifies his paycheck by serving as the household cook. He’s almost as appetitive as Turtle, but he’s the one with qualms about girls who dig him only because he’s Vince’s brother. An actor whose last serious gig was on the TV series Viking Quest, he’s now having trouble getting a job even on Vince’s coattails. (In real life, Kevin Dillon is brother to Matt.) He nonetheless shows signs of bourgeois sophistication: the meals he whips up are surprisingly well presented, and when a visitor grabs a pan and offers to cook breakfast, a hurt Johnny complains, “Hey, that’s my Le Creuset!”

Eric (“E,” Kevin Connolly) is the Zeppo, Vince’s putative manager, a fair-haired suit trying to pretend that he’s not a suit, that he isn’t as dependent on Vince’s success as everyone else. And, of course, he takes the most shit from his pals.

There’s also an ethnic ringer in the bunch. Jeremy Piven’s turn as Vince’s agent has just about stolen the show. And why not? Ari Gold is ethnic typecasting at its most potent: crude, loud-mouthed, emotional, an unabashed striver. His candid scheming is set against the silver-tongued, English-accented (naturally) hypocrisy of his former boss (Malcolm McDowell). Piven delivers his rapid-fire rants with letter-perfect technique and timing — he doesn’t so much chew the scenery as chew his way through dialogue like a stoner through an order of Chinese spareribs. He’s unstoppable.

The new season will have fans turning to the HBO Web site for last season’s episode summaries. What happened to Mandy Moore, Vince’s co-star on Aquaman? And Turtle seemed to have found a way to make himself a productive member of society without betraying his roots by hooking up as a manager for a rapper (Saigon) — what happened there?

It doesn’t matter. There’s trouble brewing in the form of a visitor from the Old Country — a member of the entourage who went bad back in the day and is just out of prison. Everyone’s welcome at Chez Vince, but here’s one lewd, crude dude from the ’hood who may be more than they can handle and who’ll keep the juices stewing in Johnny’s Le Creuset.