By using the hosts file approach I was able to visit the entry server for the Rosetta@home project, and it was running fine. I even posted on their internal forums.
However, Rosetta@home remains inaccessible today. It should take only a few minutes to fix a DNS problem, not several days. Yes, then there will be some propagation delay, but this has gone pretty far beyond the point of being ridiculous. It has reached the point where you have to wonder about the fundamental technical competence of the people running the project. That even casts doubt on their results. If they can't figure out DNS, are their MUCH more complicated algorithms and programs sound? In my own experience, the hardest problems often involve cleaning up problems with the data, but DNS problems should be much easier to clean up...

Unfortunately, this is NOT the first time I've wondered such things. On the one hand, I've been involved in a lot of these projects over the years, going back to the original seti@home project where I was in the top 1% of contributors (and where I even suggested implementing some of the features of BOINC before usenet died) and I have earned a lot of 'points' from rosetta@home, but on the other hand, maybe it's time to look for a new project and fish for recommendations?
There is the obvious workaround. If someone has a list of all of the required hosts and their current IP addresses (possibly with some aliases, too), then I could temporarily patch all of the hosts files on the various computers. Based on yesterday's test, that would probably work, but...
In terms of finding a new project, I can say that the #1 annoyance of EVERY project that I've used under BOINC was the deadlines. Apparently the BOINC client doesn't provide any scheduling help for the projects, so they can't assess how much work to download and what the deadlines should reasonably be set to. *sigh* :-<
P.S. Perhaps a bug in this system? It says to add my sig, but nothing appears?