Hot Tub Time Machine

"Hot Tub Time Machine" is about four friends who are hurled back from the dreary, weary present day to the DayGlo go-go year of 1986 by, as the title states, a recreational pool of frothing warm water. It takes less than two minutes to get to its first excrement joke. It features alcohol, drugs, foul language and nudity to a degree that would make even the most depraved libertine blush. It does not savage two genres (the '80s film and the time-travel story) with sharp claws so much as it lazily bats at them with blunt paws.

"Hot Tub Time Machine" is also unhinged, unrepentant and hilarious, unequivocally the best American comedy we've had in a long time. I did not feel proud during "Hot Tub Time Machine," but I also felt nothing between my chin and my eyebrows, as I was laughing with the brilliant stupidity of it all so hard, long and often that my face went numb.

Lifelong friends Adam (John Cusack), Lou (Rob Corddry) and Nick (Craig Robinson) need a getaway. Adam's just gone through a breakup. Lou was found in his garage, passed out drunk, with the engine running. Nick's haunted by his wife's single instance of infidelity. In desperate need of relief, they go to the ski resort they enjoyed in their youth, with Adam's nerdy nephew Jacob (Clark Duke) a last-minute addition. Lou is insisting his accident was just that ("If I wanted to kill myself, I'd f---ing kill myself! I'd be awesome at it!"), but Adam and Nick want to keep him close and unwind him a little.

After finding an unwelcome surprise in the dilapidated, run-down room's hot tub (like the boy-men who will soak in it, the ski resort's glory days are long past), the cryptic handyman (Chevy Chase) repairs the title tub. Now, it has warm water, fizzy jets and the capacity to hurl all four occupants through the space-time continuum to 1986 so that Adam, Lou and Nick are now in their teen bodies while Jacob is out of time in more ways than one.

Our foursome's reaction is, naturally, to freak out. They know they can't change anything, after a brief recap of the "Terminator" franchise's lessons on causality delivered by a cocaine-frosted Robinson. Never mind their own futures: Jacob is literally in danger of being erased, "Back to the Future"-style, if certain events don't go as they originally did on the weekend Adam, Nick and Lou are now reliving.

"Hot Tub Time Machine" sentimentalizes youth (Adam notes wistfully at one point that back then was better: "We were young. We had momentum. We were winning ..."). Yet it also mocks, knocks and ridicules the '80s as well, like when the three are mistaken for Soviet agents by Blaine (Sebastian Stan), the "Red Dawn"-obsessed, popped-collar-wearing head of the ski patrol, after he finds their iPod, Chernobyl energy drink and other future trinkets.

Written by Josh Heald and substantially rewritten by Sean Anders and John Morris of "Sex Drive," the movie has great circular gags and slow-build running jokes; the backstory behind Crispin Glover's ski-lodge bellman (one-armed in 2010, two-limbed in 1986) works superbly. There are plenty of throwaway one-liners (Lou notes of Nick's 1986 haircut: "You look like Kid 'n Play." Nick responds: "You know those are two people, right?"), but there are also big set-pieces. When Jacob warns about the butterfly effect in which one change in the time stream can have disastrous ramifications ("I write 'Stargate' fan fiction; I know what I'm talking about"), a different animal winds up demonstrating it in a over-the-top bit that goes to extremes and still works as comedy.

Directed by Steve Pink (who, having worked with Cusack on the scripts for "High Fidelity" and "Grosse Pointe Blank," gets both his leading man and the toxic allure of the '80s), "Hot Tub Time Machine" is substantially bolstered by the funny foursome on the poster. Cusack is loose and relaxed like he hasn't been in a while, and Corddry is without fear or dignity. Robinson serves back every volley he's given, and scores with a riff on a classic scene from "Back to the Future," while Duke's deadpan makes him easy to enjoy as the character more interested in living in the present (literally) than wallowing in the past.

It is hard to praise the technique in "Hot Tub Time Machine" (it was shot swiftly, and looks it), but who needs craft when you have four great leads, brilliant jokes, a savant's sense of comedic timing and structure and go-for-broke guts? I don't know if the kids will get "Hot Tub Time Machine" (there's a Scritti Politti joke, for heaven's sake), but as a popcorn pop-culture snack for aging Gen-X'ers with their own memories and regrets, it's a fun, fast, fearless comedy.

James Rocchi's writings on film have appeared at Cinematical.com, Netflix.com, SFGate.com and in Mother Jones magazine. He lives in Los Angeles, where every ending is a twist ending.