The other day I noticed some videos quit working in Google Chrome on both my Ubuntu 12.04 and 12.10 machines. HTML5 videos still worked, but Flash videos did not. I don't know if Flash is the most fragile software ever, but it certainly fails often enough that I didn't really blink. In fact, I decided to wait to see if it would fix itself. The good news is, there was a Google Chrome update this morning! The bad news is, it didn't fix the Flash video problem.
So I opened up chrome://plugins and turned off the newest flash plugin (Shockwave Flash 11.5r31), presumably letting the previous one (11.2r202) take over.
This seems to have restored Flash video capability to Google Chrome. At least, for the time being.