zero:~ brian$ rvm install jruby
jruby-1.5.6 - #fetching
jruby-1.5.6 - #downloading jruby-bin-1.5.6, this may take a while depending on your connection...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 10.9M  100 10.9M    0     0   270k      0  0:00:41  0:00:41 --:--:--  342k
jruby-1.5.6 - #extracting jruby-bin-1.5.6 to /Users/brian/.rvm/src/jruby-1.5.6
jruby-1.5.6 - #extracted to /Users/brian/.rvm/src/jruby-1.5.6
Building Nailgun
jruby-1.5.6 - #installing to /Users/brian/.rvm/rubies/jruby-1.5.6
jruby-1.5.6 - #importing default gemsets (/Users/brian/.rvm/gemsets/)
Copying across included gems
Error: dl failure on line 732
Error: failed /Library/Java/JavaVirtualMachines/1.7.0.jdk/Contents/Home/jre/lib/client/libjvm.dylib, because dlopen(/Library/Java/JavaVirtualMachines/1.7.0.jdk/Contents/Home/jre/lib/client/libjvm.dylib, 10): no suitable image found.  Did find:
	/Library/Java/JavaVirtualMachines/1.7.0.jdk/Contents/Home/jre/lib/client/libjvm.dylib: mach-o, but wrong architecture
zero:~ brian$ java -version
openjdk version "1.7.0-internal"
OpenJDK Runtime Environment (build 1.7.0-internal-b00)
OpenJDK 64-Bit Server VM (build 20.0-b06, mixed mode)
zero:~ brian$