This is due to some very aggressive firewalls permitting our sites, but not our CDN (sstatic.net). You'll hit this, unfortunately quite often, in mainland China. If you're in the Special Administrative Regions (HK/Macau, etc) then you should be fine.
You have two options:
- Go with https:// (which sometimes works)
- Go with a proxy service like Hola Internet1 or similar if that fails
It's hard to design around a use case of someone intentionally breaking the Internet, so unfortunately, there's not much we can do to get around it (if we want to use a CDN, which we really need to do). We're hoping that enough bug reports (yes, the GWOC does have a bug tracker so 'legitimate' domains can be unblocked) finally gets them to stop blocking our CDN.
1We don't officially endorse any third party proxy, I've just had luck with them, as have users that acted on my recommendation to try them.