Something has been wrong with my finder and Mac. How to fix?
There is a bug in 10.8.2 where occasionally revealing files in Finder stops working and Archive Utilility stops responding whenever you try to extract an archive.

As a workaround, you can terminate appleeventsd from Activity Monitor or with sudo killall -kill appleeventsd. (Without -kill other processes stop responding.) The issue will probably return within a few days or hours though.