Few programs on TV are as unabashedly trashy as “Californication,” the Showtime comedy starring David Duchovny as a self-destructive writer as adept at screwing up his personal life as he is at bedding extravagantly beautiful women.

And that’s both the good and bad news.

Returning Jan. 9 as part of the pay channel’s new Sunday lineup (along with the newcomers “Episodes” and “Shameless,” with reviews of those to come shortly), the series remains a lot of fun, if a trifle repetitive. After an earlier subplot that involved having Hank (Duchovny) befriend a crazy, Phil Spector-like music producer, he’s now surrounded by a bunch of insane Hollywood denizens as a book of his begins the labyrinthine route to becoming a movie, including Rob Lowe as a bonkers actor and Stephen Tobolowsky as a zany producer.

Halfway through the 12-episode season (Showtime sent out the whole bunch, but I’m saving the last six for a quieter stretch), there are an abundance of sexual trysts, auto-erotic asphyxiation and a sex-crazed monkey. In other words, just a typical few weeks within the thirty-mile zone.

By that measure, “Californication” is a bit like “Entourage” before the boys started growing up. But the series’ intermittent attempts to get serious almost invariably fall flat, as if the show is trapped by its name. When you’ve established yourself as a live-action cartoon for adults, it’s difficult to start waxing poetic about the wonders of fatherhood.

For all that, the series remains highly watchable, in a guilty, check-your-brain-at-the-door, “Wow, Carla Gugino looks great” kind of way –- providing, that is, that the show stick to its strengths and just keeps monkeying around.