Seemed to work for me, although it took a while to load and said "All systems operational"

edit: Now says "19:32 Eastern Standard TimeWe're investigating connectivity problems on github.com."

edit2: "19:47 Eastern Standard TimeWe're investigating a significant network disruption affecting all github.com services."

They also send out update on their @githubstatus twitter: https://twitter.com/githubstatus

Nothing for this yet, though.

EDIT: There it is: https://twitter.com/githubstatus/status/692505376554618883

Luckily that came back up 5 or 10 minutes after the outage began. And they updated it with a down notice.

A side project of mine called StatusGator [1] monitors status pages and alerts you when something is posted on them. I built it to handle the use case that you're trying to diagnose an issue only to remember to check the status pages of your dependencies and notice that they are already working on it.

It's pretty useful for those services that keep their pages up to date. But not very useful in cases like this when it's not updated.

1. https://statusgator.io