The good: I have repaired many services including downloads.imagej.net as well as the update sites (update.imagej.net, update.fiji.sc, sites.imagej.net). So Fiji should be downloadable again.
The bad: imagej.net and search.imagej.net are still down, and will remain down for the next couple of days as we repair and migrate them to new servers. This also means the ImageJ Updater is still nonfunctional for the moment, since it relies on a response from imagej.net.
The ugly: openspim.org is partially restored thanks to (earlier-than-planned) migration to GitHub Pages. Unfortunately, there are many rough edges not yet fixed, as visitors to that site will likely notice. But at least the main content is present and accounted for; see also the openspim.github.io source on GitHub.
I will post another status update here every day until all services are back online.