Ask just about any screenplay writer and they'll confirm the old saying about dying being easy while writing comedy is hard. Having written (sadly unsold) spec scripts in the past for TV sitcoms, I can certainly attest to that.
Yet, comedy writing is nothing compared to penning a time travel story. That is, if you want to get it right from a scientific standpoint. The problem, of course, is that doing so is next to impossible, and I once found myself in a downward spiraling writing circle of hell trying to craft such a work. Imagine then, the potential and quite probable nightmare of trying to write a time travel comedy.
As one can immediately tell by the title, that's exactly what Josh Heald and Sean Anders & John Morris have set out to do with "Hot Tub Time Machine." Continuing the trend of moving away from H.G. Wells' mechanism that was specifically made for such temporal hopping purposes, the trio of scribes have instead used the common, everyday titular device as their means of sending their characters back in time.
And in doing so, they've pretty much decided not to worry about getting the specifics of time travel accurate (if there is such a thing). Instead, they have focused on going for the laughs. Many of those naturally stem from the related "what if" elements, but rather than be concerned about the temporal ramifications of changing the past, they and director Steve Pink (2006's lame and barely seen "Accepted") have put their energies in enveloping said material with as much raunch and adult comedy content as possible.
The result does have its fair share of laughs, but a little risqué material, crudity and profanity can go a long way, and the filmmakers make the mistake of letting it pile up so much that it quickly loses much of its comedic and/or shock value. The result is an offering that will play well to the adolescent minded, but isn't as smart and/or clever as it could and probably should have been.
The plot is quite simple. Three contemporary, middle-aged guys (John Cusack, Rob Corddry and Craig Robinson) have both grown apart and disillusioned with their own lives and thus try to recapture a slice of better times by revisiting a wild, party place from their past. There, with one's 20-year-old nephew (Clarke Duke) along for the ride, they booze it up in the titular appliance, inadvertently short out the electronics, and before any of them can slur out the words "Great Scott!" or "We're not in Kansas anymore" they wake up back in 1986.
That, of course, will likely remind time travel movie aficionados of arguably the last great such flick, "Back to the Future," especially with George McFly, uh, Crispin Glover (who played him in that film) having already shown up as a bitter, one-armed bellhop before the temporal jump. He's there in the past as well, albeit still with both arms, a point that leads to a fairly hilarious set of occasional scenes where we're led to believe we're going to witness the moment of dismemberment, only to have his character barely avoid that time and again.
Beyond that cinematic reference (and having '80s star Chevy Chase showing up as a mystical hot tub repairman in an extended cameo that does little for the film, particularly in terms of generating humor), there's the usual array of making fun of how people looked and dressed back then. That's obviously easy pickings, but it's not terribly funny, and certainly doesn't have as much fun with such era comparisons as did Robert Zemeckis' film (this one even borrows that film's playing a song from the future in the past sequence, but does so far less successfully in terms of sheer entertainment).
Once the guys realize when/where they are, they alternate between trying to keep things on track for where they're supposed to be headed and wanting to change things for the better. All of which means Cusack gets involved with a past girlfriend and then a new woman; Corddry must contend with a past bully; Robinson tries to get his band mojo back while worrying that he's cheating on his wife (who's only 9-years-old in 1986); and Duke learns his mom was a promiscuous partier in the past.
That latter bit leads to an amusing if ribald riff on the circular time travel paradox of running into one's father in the past. It's too bad, however, that the filmmakers weren't more imaginative with that and other such material rather than simply falling back on crude, sexual and profanity-laden bits for the laughs. Some of the latter do work, but the film could have been so much better with a little more effort. Likewise, it could have used a bit more heart in terms of dealing with midlife crises and related angst, thus making the characters and their plight more engaging.
If you're looking for a mostly juvenile comedy with sporadically decent comedy bits, you could certainly do worse than what's offered here. For someone who's delved in both comedy and time travel writing in the past, however, I can't help but wish someone would travel back to the film's writing & shooting and suggest a number of edits and enhancements that might have turned this into a cinematic comedy classic. "Hot Tub Time Machine" rates as a 4 out of 10.