It is almost impossible to believe today, given the multimedia empire that now bears its name, that the Onion — the weekly comedy newspaper with the green masthead — was once merely the in-class diversion for a few Midwestern college students.

For anyone who attended the University of Wisconsin-Madison during the late 1980s or early ’90s, the origins of the Onion, which was founded in 1988, are well-known: It was a paper conceived, printed, and distributed by a few rambunctious students, chief among them Tim Keck and Christopher Johnson.

How the times have changed.

This year, almost as if to celebrate the paper’s 20th anniversary, the Onion has reached a turning point of exposure and ambition. What once was a semiweekly, print-only creation has grown into a semi-daily (at times semi-hourly) nationwide entertainment chain. Fans have been continually wowed by the audio, video, and online offerings that the Onion has added to its mix in the past few years, but this month marked an especially noteworthy threshold for the organization. Last week, the first feature-length Onion film, unsurprisingly titled “The Onion Movie,” arrived in stores on DVD, taking up residence alongside big-budget titles such as “Meet the Spartans” and “Semi-Pro.” Considering the rate at which the Onion has swelled, the only unusual side to the story was how little fanfare was stirred by the film’s release.

Long delayed in production (some reports suggest that the preproduction began in 2003), the film is a mishmash of some 50 different skits. Some push the envelope and miss the mark, such as a hyper-sexualized Britney Spears spoof and a murder mystery dinner party that, instead of investigating a murder, involves the investigation of a rape. But others exhibit the same snap and pop of the best Onion print headlines. One of the film’s fake advertisements spotlights a martial arts movie starring Steven Seagal, in which the hero only karate-chops adversaries in the groin. Another peculiar sketch features an armed robber who holds up a bank not for money, but for a job. As he works his way up the corporate ladder, still masked and holding a gun, he eventually finds himself confronted by a new gunman who tries to hold up the bank. Now the manager, he shoots the assailant.

The release of “The Onion Movie” might be an indicator of what is to come from the name that has consistently disrupted the comedy establishment. In some ways, it is the culmination of an evolution that began in 2001, when the Onion, growing in both prestige and circulation, moved its headquarters from Wisconsin to New York (SoHo, to be exact).

Having published its first book, “Our Dumb Century,” and launched its daily, 60-second syndicated radio spoof, “Onion Radio News,” only a few years prior, the company quickly added to its product mix when it hit the East Coast. With the advent of the iPod, those daily broadcasts were modified into some of the most popular audio podcasts on the Internet. After extensive improvements were made to its Web site (theonion.com), the company made its shift to video, launching the “Onion News Network,” its spoof of the 24-hour cable news networks.

Today, as the text version of the Onion has been reformatted for audio, and as video podcasts have been molded into the shape of a feature film, the question is where the company intends to go next. In the summer of 2006, rampant rumors that Comedy Central’s parent company, Viacom, was making a move to acquire the Onion ultimately went nowhere. Instead of merging, the outsider decided to remain a novel and nimble competitor, churning out weekly jokes via newspapers, the Internet, podcasts, and DVDs that are consistently funnier than anything being offered by the likes of David Letterman, Conan O’Brien, and the cast of “Saturday Night Live.”

ssnyder@nysun.com