In a quaint pub nestled in Canterbury, some 50 kilometres south-west of London, two young women eagerly await free drinks promised by a stranger on Facebook. Imagine this. Just post your request and if you’re lucky, free drinks will follow. It’s the kick-off of what might just be the most extraordinary drinking game in Britain right now. The young students write on Facebook: “Two broke students celebrating the end of a tough assignment period. Any drinks are welcome (except beer plz).” A photo accompanying the post shows two young women sitting in at a table in a Canterbury pub. Shortly afterw…