It appears that Google Sites, the replacement for Google Pages, might be down for a bit today. I have been getting 502 errors for more than five minutes now.
According to Google, Google Sites is "powerful enough for a company intranet, yet simple enough for a family website". While I have not heard about it from Google or anyone (including their blog) so it could be just me. :)
This is what the error message reads like:
The server encountered a temporary error and could not complete your request.
Please try again in 30 seconds.