slightly , but this thread made me think of skydiving...
in skydiving culture, any time a milestone is achieved (1st jump, 1st solo jump, 1st time pulling your reserve, etc) - the tradition is to buy beer for the drop zone.
at the place i used to jump, this WAS an enforced rule. you bought the beer for everyone every time you hit a milestone... (with a $20 max, and of course you couldn't open the beer until the airplane was tied down for the night...)
what would the homebrewer equivalent be? what should we do for milestones?