Oculus Rift headset users were unceremoniously dumped out of virtual worlds and back into the real one, yesterday, and it was all because of an "expired certificate". The workaround, until they fixed it: setting the clock back.
Rift is back online as of ~12am. This was a mistake on our end, and we apologize. Folks impacted by today's downtime will be provided with an Oculus store credit. More details to follow soon. Thanks again for everyone's patience as we worked through this one.