A mere year after Team Fortress 2 players set a new record for a single hat trade, with an absurdly rare Crone's Dome going for approximately $18,000 worth of keys, those crazy cats are at it again.

Here’s how it works. It took almost 20 years, but Team Fortress 2, the team-based FPS that changed a great many lives when it debuted in 2007, now has an SDK that Valve says will enable creators ...