Cast: John Cusack, Clark Duke, Craig Robinson, Rob Corddry, Crispin Glover.

FIRSTLY, great title. It hints at all kinds of sex-comedy silliness and back-to-the-future shennanigans, declaring loudly and proudly that this is a film that is not to be taken too seriously.

And that's exactly what the movie Hot Tub Time Machine does. It doesn't care to explain how a jacuzzi becomes a de facto DeLorean (it's involves pouring an illegal Russian energy drink into the hot tub controls... or something), nor does it get too bogged down in its butterfly effect meddlings - it just wants to be a piece of good-times stupidness.

It's four time travellers are dumped-again Adam (Cusack), his couch potato nephew Jacob (Duke), dead-end-jobber with a cheating wife Nick (Robinson) and "asshole friend" and general no-hoper Lou (Corddry), all of whom are thrown back to 1986 while on a ski trip aimed at cheering up Lou after an apparent suicide attempt.

Unfortunately they've arrived during a particularly turbulent weekend they experienced back in 1986 where Adam was dumped, Nick failed in an open mic competition, Lou was beaten up and Jacob was conceived.

At first concerned with getting back to the present and leaving the past untampered, the three older guys eventually realise they have an opportunity to do things differently and potentially improve their future lives, but the downside is that Jacob is flickering in and out of reality as their actions are inadvertantly putting his future birth at risk.

The situation is rife for humour and there are enough gags along the way to keep you laughing (with the best being Robinson's dead-pan to-camera use of the title and Corddry's incessant bastard-ness).

The four stars anchor a silly plot that would have otherwise gone off the rails and they manage to illicit enough pathos to make us give a damn about them. Only Chevy Chase's cameo as the mysterious hot tub repairman is a major let-down and wasted opportunity, while the number of potential gags that either go missing or fall flat is the only other real disappointment.

But as far as straight-faced silliness goes, this is the best hot tub fun you'll have without being in one.