There have been live auctions of high-value merchandise for over two thousand years, but the somewhat counter-intuitive idea of selling a bunch of online items offline is a relatively recent.

Domain registrar Moniker is the oldest and biggest player in the offline domain auction space, running regular domain name auctions at industry events, like T.R.A.F.F.I.C.  Moniker accounts for the majority of the top sales listed on the DN Journal list.

DomainTools is about to get into the business of real world domain aftermarket auctions, with a nifty imrpovement.  They are going to combine a real-time live auctioneer at the Seattle Domain Roundtable Conference (attending the auction is free of charge) with a simultaneous online auction.  You can bid either at the conference in Seattle, or while logged into their online system.

Both have upcoming auctions.  The Domain RoundTable auction is literally just around the corner -- it's scheduled for August 15th.  Moniker's next "Premium Domain" auction isn't until October, but its deadline for submissions is even earlier!