Let us know what you'd like to talk about, and we'll be happy to reply. Just as an FYI, the first updates to the book went out last week, and if you are thinking of purchasing, note that we'll try our best to keep it up to date either via the forums and code examples, or if needed, via more updates.
Some news or topics that may be grist for discussion here:
Roo 1.2.2 Released… The Tailor add-on is the big feature here, plus lots of bug fixes
Roo add-ons - I recently launched a few add-ons, and have a lot material on my blog, www.rimple.com.
To scaffold or not to scaffold, the debate rages (kind of)
Good uses for Roo beyond using it for RAD
Roo and other web frameworks
Active Record or Service -> Repository
So, I'm game for lots of discussion, feel free to ping me this week. I'm sure Srini is as well. He has focused on security, cloud, email, jms, and integration in the book, so he definitely can chime in there to more ability than myself. I worked most on the first 9 chapters (except security) and the two add-on chapters, so that's my area of special expertise.