Instructions are at https://github.com/diaspora/diaspora
I got as far as "Run the app server" when I ran into "Could not find rake-0.8.7 in any of the sources".
update:
had to install rake separately. still having the problem.
Another update:
Where the instructions say 'bundle install', use 'sudo bundle install'
update:
not sure about above. Now mongodb starts, yet isn't running an instant later.
--
I had mongodb installed from before from default ubuntu sources, apparently a broken install.
confusion running the client, trying the test suite.
...
tests passed.
figured out login, https://localhost:3000/login
looks like I have a working install.