If you are of a certain age, it's the defining moment of your youth as a sports fan.

Bill Buckner's missed grounder gave the New York Mets a dramatic win in Game 6 of the 1986 World Series. That play helped keep the Boston Red Sox without a championship for another 18 seasons.

Besides being an important piece of American sports history, Buckner's ball has a tremendous amount of value to sports memorabilia collectors. We'll soon find out just how much.

An unknown fan will become the owner of this prized memento of the 1986 World Series gone wrong for Boston, when the club was just one strike away from winning.

Friday, the Buckner Ball will be sold at Heritage Auction Galleries in Dallas.

Seth Swirsky is the current owner of the ball. The Grammy-nominated songwriter purchased it from wild child actor Charlie Sheen for $63,500 twelve years ago. Sheen had picked up the ball at auction for $93,000 in 1992.

By the way, Swirsky's claim to fame is writing Taylor Dane's "Tell It to My Heart," the 1987 dance-pop song. In case you've forgotten about that awesomeness, here it is:

"What happened with that play goes beyond baseball," Swirsky told the Dallas Morning News. "The magic of that ball is that the Mets and their fans got as high as you could possibly get, and the Red Sox, the team and the fans, got as low as you could possibly get...And that ball represents both."

Swirsky is unloading his full 240-piece collection of sports keepsakes, yet it's the Buckner Ball that is the star of the auction.

As of late Wednesday the leading online bid was $90,000. But when the real auction kicks off Friday, it's expected to sell in the neighborhood of over $100,000.

That's one nice neighborhood!

-- Follow Ben Maller on Twitter @BenMaller.

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