Imagine a room filled with retro machines, humming with new life as their proud owners show them off. This isn't a scene from a classic car show. Instead, these hobbyists fix up old computers and showing them off to fellow "chipheads."

Pavl Zachary complements his '70s-era PDP 11/40 computer with period-appropriate sideburns and mustache at Vintage Computer Festival East 7.0 in 2011. Vintage Computer Festival

"Basically, we're the exact same thing as an antique car club," Evan Koblentz, president of the Mid-Atlantic Retro Computing Hobbyists (MARCH), told TODAY.

Koblentz and his fellow enthusiasts fix up everything, from "Mad Men"-era computers daing to the mid-1960s, to devices from the 1980s. Anything older than that, Koblentz said, is a "museum artifact" and anything newer a "used car, not an antique one."

The goal isn't to simply to collect old computers. It's to spend time hunting for parts and tinkering with them until you can hit the power button and turn on a fully functional computer. Then they are shown off at events like the Vintage Computer Festival that take place at locations across the country.

"If you went to an antique car show and touched some guy's '34 Chevy, he would cut off your finger on the spot," Koblentz said. "At our shows, we require all exhibitors to have everything up and running to let people play with them."

Fixing up an Apple IIe, which you can find on eBay for $50, is considered retro-computing 101. These guys are working with some really old stuff: mini-computers from back when "mini" meant anything that was not a giant mainframe, models from extinct brands like DEC and Data General, and "big iron" computers the size of armoires. Sometimes all that’s needed to find the right replacement parts is a Google search. Sometimes a fix-up job requires a degree in electrical engineering.

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Yes, some of these computers are worth money. Last year, an extremely rare Apple 1 hand-built by Apple co-founder Steve Wozniak in 1976 sold for more than $900,000 at auction. The MITS Altair 8800 might fetch you around $2,000 or $3,000. For the most part, however, the machines don't have a lot of financial value.

"This is a hobby, not an investment," Koblentz said.

MARCH formed 10 years ago as a way for "local members to get together, drink beer, and mess around with old computers." It's now a non-profit organization housed in a wing of the InfoAge Science Center in Wall, New Jersey with around 40 to 50 active members.

There are similar groups scattered throughout the country. Dave Cooper is a member of the Seattle Retro-Computing Society. Back when he was in college, he wanted a MicroVAX computer, but couldn't afford one.

Six years ago, he decided to look for one online. He fixed it up and soon became hooked, refurbishing hundreds of computers he keeps in his basement and several storage lockers.

Cooper, a software developer, now sees his work as more than just a hobby. He sees old computers being thrown away or sold for gold scrap. The instruction manuals are mostly lost and the people who know how to use them are getting older and will eventually pass away.

"In my opinion, the computer is the most important invention in human history," Cooper told TODAY. "I can contribute to the preservation of this history."

For others, the impulse to fix up old computers is based solely on nostalgia. A Colorado man named Jeff Keacher saw histale of how he rigged a Mac Plus from 1986 to surf the modern Web become a viral hit. The computer was already out of date when Keacher used it as a kid in the 1990s. Back then, he used to connect to bulletin board systems, or BBSes. Now, after spending decades in storage, the machine is an absolute dinosaur.

Frank LaRosa with his TRS-80 Model 3 at Vintage Computer Festival East 7.0 in 2011. Vintage Computer Festival

He spent a month looking for parts and devising MacGyver-like fixes to modernize the computer. It now can connect to modern websites and display them with surprising readability — minus photos, videos and pretty much anything but basic text.

The problem? It takes a very long time to load pages.

"When I started the project, I thought it would be neat to put it in the living room and let people look up stuff on the Web," Keacher told TODAY. "The reality is that it's so slow, it's more of a novelty than a useful tool."

One common goal in the retro-computing community is to make old computers tweet. As far as Koblentz knows, the record for the oldest computer ever connected to the Internet is the Commodore VIC-20.

This is Richard Beales tweeting from the VIC_20 at the Personal Computer Museum in Brantford, Ontario, Canada. http://www.pcmuseum.ca — PC Museum (@vintagepc) February 20, 2010

Not that most people who do this are looking for an alternative to Twitter on their iPhone.

"Anyone who tells you that they use their 40-year-old computer every day is kind of exaggerating," Koblentz said. "Most of us do it because it's fun and we want to take them out for a Sunday drive."

Keith Wagstaff writes about technology for NBC News. He previously covered technology for TIME's Techland and wrote about politics as a staff writer at TheWeek.com. You can follow him on Twitter at @kwagstaff and reach him by email at: Keith.Wagstaff@nbcuni.com