Building a website for Drupalcon.org is a challenging matter. There are lots of features to work with, the site should adapt to the needs at any time and of course should show that when Drupal is used to build its own conference website, it should do cool stuff for its attendees and other interested parties.
There were lots of design decisions made on the site given the needs we specified based on our look at previous Drupalcons and our own expectations. Sometimes existing modules fit well into our plans, quite a few times we needed glue code or our own code to do the work. Sometimes our own code resulted in superb end results but then also sometimes made mistakes. It also turned out that some of our design choices were not perfect and in some cases our implementation was not adaptive as we wished.
I hope to tell stories about these experience, dive into some details about the implementation, glue code, own code. You will most probably not get clear recipes, and definitely not ready to use code.
Ps. (If we have time and interest, we can get into the making of do.drupaltown.org - our management website for this event and lessons we learned using and sometimes not using that).