I first got it running on Windows where on the 'Choose SDK' step of the wizard I selected Ruby SDK and pointed it at
C:\Rubywhich worked just fine. IntelliJ figured out it was Ruby 1.8.4 and all was happiness and light.
Then I tried the same thing on Linux (I'm using 6.06 Dapper). A
/usr/bindidn't work since that
rubywas a file. Starngely,
/usr/lib/rubydidn't work either.
After randomly trying to point IntelliJ at various sub-directories, I decided to compare the directory stucture with that of my Windows installation which had worked out of the box.
/usrwas the directory which matched
c:\ruby. When I pointed IntelliJ at
/usr, it picked up the Ruby SDK right off and everyone lived happily ever after.