Using the binaries. Tried both 10.6 and 10.8 osx app versions. System running 10.8.5. Sage does not appear to load. The following appears at the end of the log:
File "/Applications/Sage-5.12-OSX-64bit-10.6.app/Contents/Resources/sage/local/lib/python/sre_constants.py", line 18, in <module> from _sre import MAXREPEAT ImportError: cannot import name MAXREPEAT