Microsoft Office Developer Conference
For last 4-5 years I've attempted to evangelize OBA - office business applications. Those are extensions to Microsoft Office - Outlook, Word, etc which extend them to match business processes.
The idea finally got traction and right in this time Microsoft happened to host Microsoft Office Developer Conference in San Jose.
The conference was good, but short - 2 days of compressed information with 3-4 "need to be there" parallel sessions.
I've concentrated on architecture sessions and by the end of conference had pretty solid architecture design.