This appears to be becoming a regular thing - Google uploading developer hangouts (from Google+) to YouTube for all to watch and learn from. We recently looked at one about Chrome Developer Tools and one on developing for Chrome For Android.
Today's is all about WebGL. It's about an hour long, and it's full of Googlers who have plenty to say on the subject, including some discussion about some map-related things the company has been discussing at Strata and a SXSW.
Google has a workshop area of its WebGL experiments site here, which you may also find of use.