Many people who find an old copy of Monopoly hope they've hit the jackpot, that it will be worth thousands of dollars on eBay and will finance a nice vacation. Sadly, that's not often the case -- for any number of reasons (too many copies exist, a copy is in poor condition, etc.) most used / vintage board games don't sell for all that much money. Still, it's fun to dream.
The folks at Purple Pawn researched recently completed eBay auctions and developed this fantastic list of the 20 most valuable vintage board games that they found. The list does include Monopoly (#9, $760), but it was a version from 1933 -- before the game was widely available.
The top game on the list is Hank Bauer's Be a Manager, a baseball game published by Bamco in 1967 which sold for $1,500. In addition to truly "vintage" games, the list does include some more modern entries: War of the Rings Collector's Edition (#3, $1,200, published by Fantasy Flight Games in 2010), Settlers of Catan 3-D 10th Anniversary Edition (#8, $775, published by Mayfair Games in 2005), Axis & Allies 50th Anniversary Edition (#11, $588, published by Avalon Hill / Hasbro in 2008).