For art collectors, it's the Mona Lisa. For baseball card enthusiasts, it's the $1 million Honus Wagner tobacco card.
Motorcyclists dig the 1948 Indian.
For Dean Brosious, the Holy Grail of his hobby -- collecting and restoring antique tractors -- would be a 1913 Waterloo Boy. Only 20 were made.
"It's very highly sought after," said Brosious, a Craig resident and events coordinator and past president of the Yampa Valley Antique Power Club.
Brosious is one of 50 active members of the club, which dates back to the mid-1980s. The club defines an antique tractor as power equipment produced before 1960.
Summer is an active time of year for club members. They are coming off last weekend's successful tractor pull during Grand Olde West Days and are planning another large event for later this month.
The Yampa Valley Antique Power Club Tractor Ride and Poker Run, which entails a 14-mile jaunt through Craig, is set for 10 a.m. June 14. The club also will have a tractor show and pull Aug. 11 and 12 at the Moffat County Fair and Aug. 19 and 20 at the Routt County Fair.
Although Brosious' collection doesn't boast any equipment as coveted as the Waterloo Boy, it isn't exactly a pile of rusted gears and sprockets, either.
His collection includes five tractors, ranging from his personal preference of John Deeres to Farmalls.
They date from 1931 to 1953.
Depending on their condition, restoring old tractors can take a year or two, Brosious said.
The allure of rebuilding them, he added, lies with the thrill of breathing life back into a once-proud machine.
"It's a unique opportunity to bring something back that has been discarded or left to rot," he said.
But it's not enough to rebuild the tractors. After they're refurbished, they need to be let loose.
"To restore them and take them out is the enjoyable part," Brosious said. "(The club) provides you with something to do with them."
It's done just that for Dale and Gwen Rickerby, a Craig couple who have been antique power club members for the past four years.
"It's a fun thing do," Gwen Rickerby said. "It's a fun hobby."
The couple has rebuilt two tractors, and they own two others that they purchased already rebuilt. One of those tractors, a 1942 John Deere LA, was in pieces in Utah and nearly scrapped.
The machine was saved from the scrap heap, rebuilt by a local resident and sold to the Rickerbys.
Such is the dedication the couple has for the green and gold of the John Deere company, which dates back to 1848.
"That's the only color here," she said.
The Yampa Valley Antique Power Club meets on the third Wednesday of every month. Meeting places vary from restaurants around town to members' homes.
For more information, call Brosious at 824-3588 or club president Smoky Werner at 824-9565.