One note, I am a fan of rapid ideation which is often hard to do in DHTML. Sketching as Bill Buxton points out is an incredible way to do this. Both Flash Catalyst and Microsoft Expression Blend 2 (version announced this week) get us closer to this vision. But often we need to prototype directly in the technology of our web site (often DHTML). This talk works to point out ways to make this faster and more error free.
Prototyping can be challenging. Especially prototyping in DHTML. But over the last few years a number of tools, techniques, libraries and frameworks have emerged making the task easier. Drawing from years of experience at companies such as Yahoo! and Netflix, come hear Bill Scott discuss these solutions and best practices for laying out pages rapidly, injecting interactive behavior and simulating data for prototyping your Web applications in DHTML.