Attended my first meeting of the Sydney PHP Group the other night. A reasonably small affair, but with a very good talk from the founders of the site Remember the Milk. It was good to see two passionate and talented people talk about all the work they have done, the boundaries that needed to be pushed, and some of the pitfalls they have encountered. A lot of Free and Open Source Software is used (some of which they created) based around PHP, Python, web servers and postgress as the db. And it makes good use of AJAX technologies. I can see the purpose rather than a gimmick. Inspiring for a couple of ideas I am working on.
There is a pdf of the presentation, which includes relevant links.