I recently became aware of the following webcast about Report Builder, the framework for ad-hoc reporting in SQL Server 2005 (Yukon).
 
 
To my knowledge, Report Builder is based on the ActiveViews technology that MS purchased in Spring '04.
 
I haven't had an opportunity to view this webcast yet, but wanted to link it so that others were aware (and so that I can easily find the link later when I'm ready to view it myself ... ;)
 
cheers,
~stuart