Okay! A fun story about Venture the Void.
It ran out of disk space. Hahah =) There is a process which routinely backs up all the data files, by uploading them to my webhost, but I had forgotten that it also creates a local copy of it. This is fine, as the data files, once compressed, are quite small. But the server ran out of space, causing various failures.
Mainly, though, dns failed! So the server was still connected to the net, but probably some temp file that dhcp creates on linux wasn't being written properly (I guess) so the server couldn't do a lookup on the game database. Ergo, the server wouldn't start.
That's all fixed now, but it's sort of scary to run out of disk space. Luckily, it doesn't seem that any game data was lost, but it's kind of like, meep!