I'm sorry for the error. I shouldn't have submitted it to hacker news right before leaving for a meeting. Lesson learned, it's fixed now.
The reason, in case anyone is interested: the footer shows the most recent posts. Someone created some posts that contained data that I wasn't expecting. That caused the footer to raise an error. I removed the recent posts from the footer (from my phone, before the meeting) and the site returned to normal.
I'm really sorry for the error, but I learned something from it, so thank you!
PS, existing blogs weren't affected, it was only the homepage.