“Big Trouble,” the new comedy from director Barry Sonnenfeld (“Men In Black”), is one of the more enjoyable films in recent memory to be about absolutely nothing. This zany, random, off-kilter slapstick farce seems to actually revel in the vastness of its nothingness. There is no background, motivation, or logic behind the character’s actions — they simply do stuff, and bad stuff happens as a result. Yet not for one second does it take itself too seriously. The result is a refreshing journey through the inanity of the human mind.

Explaining this ridiculous journey in any sort of coherent, readable plot synopsis is like trying to put into words why Tom Green still has a career. In the spirit of the film, here’s an incoherent recitation of events: a high school assassins-like game collides with two angry mobsters leading to many broken televisions as well as the discovery of a nuclear weapon hidden in a bar with some Russians and an aimless wanderer (Jason Lee) that leads to a horny policeman, some goats, a bitter wife, and a washed-up columnist in a crappy Geo driving to the airport.

Although laden with so many characters and plot lines, the film never loses you for a second. It is complexity for dummies, a very straightforward explication of goofy coincidences. Yet by never basing itself in reality, film cliches, or understandable character motivation, “Big Trouble” becomes a wonderfully unpredictable joy ride.

Mindless comedies of the past, such as “Airplane!” or “The Naked Gun,” feature predictable narratives in order to focus on money moments of laugh-out-loud hilarity. While those classics are always a joy to watch, Sonnenfeld’s film passes on big guffaws in favor of a plot that traverses new territory without saying anything particularly new. The result is inspired irreverence that is effective as a completed whole — humor that does not cater directly to the funny bone.

The film is hit or miss with its eclectic mix of characters. Fortunately, the cast is big enough to allow for some fizzle amidst lots of sizzle. Janeane Garofolo, who plays a policewoman, needs to find a new shtick: her passive, unsympathetic, and dry sense of humor appears especially tired in her zany surroundings. Johnny Knoxville also fails to acclimate to the film’s “cut loose” silliness, a surprise considering the “Jackass” star has made a name for himself doing stupid, random stunts like sticking his hand up a cow’s ass and swimming in sewage.

The rest of the cast is having a blast. Rene Russo and Tim Allen maintain the wackiness with a nice mixture of stern responsibility and electric sexual tension. Dennis Farina (“Get Shorty”) turns a restaurant confrontation scene into one of the film’s most satisfying moments. And Jason Lee’s performance as a kind, Christ-like drifter is a nice display of range for the actor, who is usually stuck playing whiny, horny losers.

Unfortunately, current real-world tensions cause the giddy fun to lose steam as the film approaches its climax. A well-executed jab at absent-minded airport security may have been funny before Sept. 11, yet the simple transfer of a nuclear bomb onto a plane is a little too uncomfortable today.

“Big Trouble” was originally intended to open in late September; the delay was an incredibly smart decision, yet no amount of time can lessen the gap between the film’s fun, freewheeling ridiculousness and the scary reality of its final commentary.