Me too :(
For the record, I also experienced this on two accounts on two android devices (Friday evening). Interestingly, a laptop left turned on was still logged in and functioned fine. I couldn't however change the passwords for the accounts as google claimed the original password I typed was incorrect. Answering a few security questions got me a authorisation code which I used to log in and change my passwords. I haven't re-enabled access on the Android devices yet and won't until I get some news about what caused it.
Interestingly I had only hours earlier, made comments on FB regarding the extent of the capabilities of GCHQ for interception and attacks. I thought for a moment I was being 'slapped' by them :) for daring to comment about them. Not that my boring emails or SM posts would reveal much to them or are of any security concern, at least I don't think so ;)