Though it was publicly displayed a couple of days before, I announced the release of TurboGears on September 17, 2005: Blue Sky On Mars » Blog Archive » Announcing TurboGears web megaframework (Python).
Thanks again to everyone who has made TurboGears a successful and fun open source project!
Ah! The memories of watching the 20minWiki the first time that day.
It have been a fun ride indeed.