'Hot Tub' sequel is lukewarm - at best

★½ out of four stars
Rated: R.

John Cusack has been reduced to Z-grade action comedies shot in Australia and co-starring Thomas Jane at this stage of his career.

And he still turned down the payday that "Hot Tub Time Machine 2" promised, which tells you all you need to know about this half-baked sequel.

It's just as well, as Cusack was basically the aging straight man in the first version of this stoner time-travel comedy. Craig Robinson walked off with the picture, about three friends and a young guy who turns out to be the son of one of them, guys who travel back to a pivotal 1986 ski weekend from their past in what appears to be a hot tub electrical accident.

The sequel is dominated by Rob Corddry, a fearless funnyman best taken in tiny doses. The doses aren't tiny enough and the laughs are few and far between this time in the tub.

Lou (Corddry) and Nick (Robinson) have used the time travel hindsight to "invent" Google (Lougle) and steal every pop song between 1986 and the present, hits by Lisa Loeb to Nirvana. They got rich and famous.

Jacob (Clark Duke), who found out Lou was his dad, just got bitter. He was the smart one, after all, the one who could keep track of the time travel "science." He just failed to cash in.

"The hot tub doesn't take you where you want to go. It takes you where you need to go."

Since Lou's been shot and the guys want to foil that assassination attempt, they "need" to go back in time again. So naturally, they go into the future.

"Like in 'The Terminator,' " they crack. "Like 'Back to the Future.' Like 'Looper.' "

As running gags go, this one runs straight into the ground.

"Like in 'Lawnmower Man.' "

The "out there" stuff here includes full-frontal nudity, forced gay sex on TV and nose candy jokes. The funniest bits involve Nick's music, his rip-off of Lisa Loeb's "Stay" — a big burly black man singing a woman's romantic lament, mimicking the music video that went along with it.

Adam Scott shows up as the Cusack character's son, a dull, dopey FutureMan who tags along with the guys and goes on a fish-eye lens drug trip for comic effect.

There aren't long dead stretches, but "Time Machine 2" doesn't have much in the line of high points, either. It sort of bubbles along, one crude running gag after another, the sort of film, like the original, that will play better on home video where fans can indulge in altered states themselves, just like their heroes.