The title seems to say it all, as with the dumb but successful "high-concept" comedy, Snakes on A Plane. But Hot Tub Time Machine turns out to be a peculiar and often surprisingly effective hodgepodge of genres and comic styles.
This unabashedly silly and exuberantly vulgar story, about three disgruntled "Generation X" men who travel back in time to 1986 together with a very 2010, computer-obsessed youth, is part homage to '80s teen films, part a modern male-bonding gross-out comedy in the style of The 40 Year Old Virgin, and part intelligent generational satire. It is at times shockingly politically incorrect, with an attitude to disability, homosexuality and straight male fear of the same that some could easily find offensive.
As the film begins, disillusioned fortysomething Adam (John Cusack) has been dumped by his girlfriend. His friend Nick (Craig Robinson, from the US version of The Office), who was once a promising musician, is nearing the end of his tether over his job in a pet store and his domineering wife's infidelity. His other best friend Lou (Rob Corddry) is an angry, pathetically juvenile, alcoholic misanthrope who almost asphyxiates himself in his car while headbanging to the '80s band Mötley Crüe.
Worried that Lou was trying to kill himself, Adam and Nick decide to cheer him up by taking him on a trip to a ski resort where they spent epic weekends back in the 1980s, when as Adam says, they all still had "youth and momentum". They take with them Adam's nephew Jacob (Clark Duke), a virginal geek who spends all his time playing video games in the basement.
However, the resort has fallen on hard times. Though they have the same hotel suite they partied in on their last great weekend 24 years ago, it is now repellently shabby.
The yearning for a second chance is heart-felt
The three older men drink gloomily in their room, realising how much they have grown apart. Then a supernatural hot-tub repairman (Chevy Chase) fixes their outdoor Jacuzzi, all four men take the plunge, and thanks to the magic of this unlikely time machine, they find themselves back in time, but in their old bodies. They are simultaneously delighted and horrified to be back in the groovy, pastel-coloured past. However, the repairman appears and makes it clear that if they do anything differently than they did two decades before, they may not be able to get back to 2010; they might even alter the future and cause Jacob not be born.
That means that Nick will have to have sex with a groupie even though he wants to be loyal to his future wife. Adam will have to break up again with a girlfriend whom he now thinks was The One. And Lou will have to let himself get beaten up once again by the head of the ski patrol (Sebastian Stan, playing a classic '80s teen-movie villain). All three men are tempted to do things differently and change the direction of their lives. Jacob in the meantime has to deal with meeting his own mother when she was a sluttish ski bunny.
With contributions by at least three screenwriters of differing sensibilities, there is some genuine wit here as well as some witless and even disgusting gross-out stuff.
Inevitably, given its scattershot approach and slapdash direction by Steve Pink, some of its jokes fall flat, but others are hilarious. Though there are plenty of visual and fashion-oriented gags at the expense of 1980s - neon spandex ski costumes (much exaggerated here), big hairstyles, leggings etc - and though John Cusack's character reminds his pals that what they remember as a teenaged paradise of sexual opportunities was the age of "Reagan and Aids", there are also hints that that some things were truly better in the pre-email, pre-text era.
But the most interesting thing about Hot Tub Time Machine is the way the comedy is underpinned by regret and anger about lives not well-lived. The subtext of middle-aged yearning for a second chance is so visceral and so apparently heart-felt on the part of the filmmakers that it stays with you after the laughs have tinkled away. Even the film's happy but logically dubious ending is not quite enough to dispel a sense of generational disappointment.
John Cusack, who has not been in a decent film for a decade, plays a version of the character that made him in an '80s star. Clark Duke the young, pudgy and physically unprepossessing star of the youth comedy Sex Drive once again reveals fine comic timing. But the strongest performance in the film comes from Rob Corddry, a frequent guest on the popular American television series The Daily Show. There is also an extended cameo by Crispin Glover (who appeared in Back to the Future) as a bad tempered, one-armed bellhop.
Hot Tub Time Machine is nowhere near as consistently funny as Superbad or the Hangover, but it is a more interesting artefact, and a film that you can imagine being watched more than once by people who remember the '80s with a mixture of horror and affection.