I’ve not seen this mentioned over at the Google Help page, but it understands plain English time zone requests, so asking it:
does exactly what you’d expect: the current local time at the top of the page, and a list of links for the rest of it. Very handy, as I rarely need a full blown world clock, but just need to check it’s sane to make a call.
Now I just have to sit back and wait for the people saying: “Yup, been using it for the last 24 months”… If you have, could you tell me where you discovered it ? Just in case there’s a super-secret page of not-even-beta Google features I’m missing out on.