If you were not able to go to the OSCON 2011, don't lose heart. O'Reilly has done a wonderful job of recording the HTML5 sessions into this series. I was amazed at the quality of the recording and the content of the materials. Clearly, this series is presented by the best of the best techies. If you can devote roughly 11 hours of your time to go through these presentations, you will be well ahead of your peers. I believe it is extremely valuable to me. I learned quite a few new things related to architecture, technologies, and tips and tools.
I totally recommend buying this series or getting your employer to buy it for you. It will definitely improve your productivity, expand your thinking into creating better design, make your applications scalable, help you think about managing a large project, etc. I could just go on extolling the virtues of the presentations. I definitely look forward to next year.