The forum was down yesterday for what appears to be about eight hours. From approximately 11AM to 7PM local time. It was a "500" error, which is a generic, unspecified server error.
Fortunately, we use a small, independent hosting company, and get excellent and personalized service and support. I don't have a follow-up on exactly what was wrong right now. I'll pick it back up again on Monday - let them enjoy the rest of their weekend.
If I remember correctly, this was our longest outage. By probably double or more. Downtime is always unfortunate, but at this point we have a better record than Facebook and Twitter. Not bad for about $200/year.
Updates were given on the GroupMe text group. Possibly not tremendously helpful due to the technical server-side nature of the problem. But an announcement of downtime, acknowledgement that technical support had successfully been contracted, and an alert that the forum was back up. If you're not a member, feel free to send me your text number, and I'll add you. No one else will see your number.
Related: we also found out yesterday that apparently people prone to blocking strange numbers don't get the GroupMe texts. If you're on the text group but not getting texts, you can read on the GroupMe app.