Install twice...

gistfile1.txt

C:\>choco install ruby -version 1.9.3.54500
Chocolatey (v0.9.8.27) is installing 'ruby' and dependencies. By installing you accept the license for 'ruby' and each dependency you are ins
talling.

ruby v1.9.3.54500
Downloading ruby 32 bit
  from 'http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-1.9.3-p545.exe?direct'
Installing ruby...
ruby has been installed.
ruby has finished successfully! The chocolatey gods have answered your request!
Adding 'C:\tools\ruby193\bin' to the local path
ruby has finished successfully! The chocolatey gods have answered your request!
Finished installing 'ruby' and dependencies - if errors not shown in console, none detected. Check log for errors if unsure.

C:\>choco install ruby -version 2.0.0.48100 -debug
DEBUG: Running 'Append-InstallLog' with chocoInstallLog:''
DEBUG: Arguments: $command = 'install'|$force=False
|$prerelease=False|$packageNames='ruby'
|$source=''
|$version='2.0.0.48100'|$allVersions=False
|$overrideArguments=False|$InstallArguments=''
|$localonly=False|$verbosity=False|$debug=True|$quiet=False
|$name=''|$ignoreDependencies=False|$forceX86=False
|$packageParameters=''
|PowerShellVersion=2.0|OSVersion=6.1.7601.65536
DEBUG: Running 'Chocolatey-Install' for 'ruby' with source: '', version: '2.0.0.48100', installerArguments:''
DEBUG: Running 'Chocolatey-NuGet' for ruby with source:''. Force? False
Chocolatey (v0.9.8.27) is installing 'ruby' and dependencies. By installing you accept the license for 'ruby' and each dependency you are ins
talling.
DEBUG: Installing packages to "C:\ProgramData\chocolatey\lib".
DEBUG: Running 'Run-NuGet' for ruby with source: '', version:'2.0.0.48100'
DEBUG: ___ NuGet ____
DEBUG: Running 'Get-ConfigValue' with configValue:'useNuGetForSources'
DEBUG: Running 'Get-UserConfigValue' with configValue:'useNuGetForSources'
DEBUG: After checking the user config the value of 'useNuGetForSources' is ''
DEBUG: Value not found in the user config file - checking the global config
DEBUG: Running 'Get-GlobalConfigValue' with configValue:'useNuGetForSources'
DEBUG: After checking the global config the value of 'useNuGetForSources' is 'false'
DEBUG: Running 'Get-UserConfigValue' with configValue:'sources'
DEBUG: Running 'Get-GlobalConfigValue' with configValue:'sources'
DEBUG: Using global sources
DEBUG: Using '-Source "https://chocolatey.org/api/v2/;"' as the source arguments
DEBUG: Calling 'C:\ProgramData\chocolatey\chocolateyinstall\nuget.exe' install ruby -OutputDirectory "C:\ProgramData\chocolatey\lib" -Source
 "https://chocolatey.org/api/v2/;" -NonInteractive -NoCache -Version 2.0.0.48100
DEBUG: Installing 'ruby 2.0.0.48100'.
Successfully installed 'ruby 2.0.0.48100'.
DEBUG: Evaluating NuGet output for line: Installing 'ruby 2.0.0.48100'.
DEBUG: Evaluating NuGet output for line: Successfully installed 'ruby 2.0.0.48100'.
DEBUG: NuGet installed ruby. If we are ignoring dependencies (False) then we will clean this up.

ruby v2.0.0.48100
DEBUG: Running 'Delete-ExistingErrorLog' for ruby
DEBUG: Looking for failure log at 'C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\failure.log'
DEBUG: Running 'Run-ChocolateyPS1' for ruby with packageFolder:'C:\ProgramData\chocolatey\lib\ruby.2.0.0.48100', action: 'install'
DEBUG:   __ PowerShell install (chocolateyinstall.ps1) __
DEBUG:   Looking for chocolateyinstall.ps1 in folder 'C:\ProgramData\chocolatey\lib\ruby.2.0.0.48100'. If chocolateyinstall.ps1 is found, it
 will be run.
DEBUG: Action file is 'chocolateyInstall.ps1'
DEBUG: Running 'C:\ProgramData\chocolatey\lib\ruby.2.0.0.48100\tools\chocolateyInstall.ps1'
DEBUG: Running 'Get-BinRoot'
DEBUG: Running 'Install-ChocolateyPackage' for ruby with
url:'http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-2.0.0-p481.exe?direct', args: '/verysilent /dir="C:\tools\ruby200"
/tasks="assocfiles,modpath"', fileType: 'exe', url64bit:
'http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-2.0.0-p481-x64.exe?direct', checksum: '', checksumType: '', checksum64: '',
checksumType64: '', validExitCodes: '0'
DEBUG: Running 'Get-ChocolateyWebFile' for ruby with url:'http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-2.0.0-p481.exe?direct',
 fileFullPath:'C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe',
url64bit:'http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-2.0.0-p481-x64.exe?direct', checksum: '', checksumType: '', checksum64:
 '', checksumType64: ''
DEBUG: Running 'Get-ProcessorBits'
DEBUG: CPU is 64 bit
DEBUG: Setting url to 'http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-2.0.0-p481-x64.exe?direct' and bitPackage to 64
DEBUG: Running 'Get-WebHeaders' with url:'http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-2.0.0-p481-x64.exe?direct', userAgent:
'chocolatey command line'
DEBUG: Setting the UserAgent to 'chocolatey command line'
DEBUG: Web Headers Received:
DEBUG:   'Content-Disposition':'attachment; filename = rubyinstaller-2.0.0-p481-x64.exe'
DEBUG:   'X-Checksum-Sha1':'3a2a13eca15b48663f6c7e3ed3253e8a189e7f0f'
DEBUG:   'X-Cache':'MISS from nomad'
DEBUG:   'X-Cache-Lookup':'MISS from nomad:3128'
DEBUG:   'Connection':'keep-alive'
DEBUG:   'Accept-Ranges':'none'
DEBUG:   'Content-Length':'17574778'
DEBUG:   'Cache-Control':'max-age: 172800'
DEBUG:   'Content-Type':'application/octet-stream'
DEBUG:   'Date':'Sun, 20 Jul 2014 21:47:08 GMT'
DEBUG:   'ETag':'3a2a13eca15b48663f6c7e3ed3253e8a189e7f0f'
DEBUG:   'Last-Modified':'Sun, 11 May 2014 16:03:47 GMT'
DEBUG:   'Server':'nginx'
DEBUG:   'Via':'1.0 nomad (squid)'
Downloading ruby 64 bit
  from 'http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-2.0.0-p481-x64.exe?direct'
DEBUG: Running 'Get-WebFile' for C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe with
url:'http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-2.0.0-p481-x64.exe?direct', userAgent: 'chocolatey command line'
DEBUG: Setting the UserAgent to 'chocolatey command line'
DEBUG: Checking that 'C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe' is the size we expect it to be.
DEBUG: Verifying remote checksum of '3a2a13eca15b48663f6c7e3ed3253e8a189e7f0f' for
'C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe'.
DEBUG: Running 'Get-CheckSumValid' with file:'C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe', checksum:
'3a2a13eca15b48663f6c7e3ed3253e8a189e7f0f', checksumType: 'sha1'
DEBUG: Calling command ['C:\ProgramData\chocolatey\chocolateyinstall\tools\checksum.exe' -c3a2a13eca15b48663f6c7e3ed3253e8a189e7f0f
"C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe"] to retrieve checksum
DEBUG: 'C:\ProgramData\chocolatey\chocolateyinstall\tools\checksum.exe' exited with 0
DEBUG: Verifying package provided checksum of '' for 'C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe'.
DEBUG: Running 'Get-CheckSumValid' with file:'C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe', checksum: '',
checksumType: ''
DEBUG: Running 'Install-ChocolateyInstallPackage' for ruby with file:'C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe',
 args: '/verysilent /dir="C:\tools\ruby200" /tasks="assocfiles,modpath"', fileType: 'exe', validExitCodes: '0'
Installing ruby...
DEBUG: Running 'Start-ChocolateyProcessAsAdmin' with exeToRun:'C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe',
statements: '/verysilent /dir="C:\tools\ruby200" /tasks="assocfiles,modpath" '
DEBUG: Elevating Permissions and running C:\Users\ADMINI~1\AppData\Local\Temp\chocolatey\ruby\rubyInstall.exe /verysilent
/dir="C:\tools\ruby200" /tasks="assocfiles,modpath" . This may take awhile, depending on the statements.
DEBUG: Finishing 'Start-ChocolateyProcessAsAdmin'
ruby has been installed.
ruby has finished successfully! The chocolatey gods have answered your request!
Adding 'C:\tools\ruby200\bin' to the local path
ruby has finished successfully! The chocolatey gods have answered your request!
DEBUG: Running 'Get-ChocolateyBins' for C:\ProgramData\chocolatey\lib\ruby.2.0.0.48100
DEBUG:   __ Executable Links (*.exe) __
DEBUG: Looking for executables in folder: C:\ProgramData\chocolatey\lib\ruby.2.0.0.48100
Adding batch files for any executables found to a location on PATH. In other words the executable will be available from ANY command
line/powershell prompt.
DEBUG: Found '' for batch redirect
DEBUG: There are no executables (that are not ignored) in the package.
DEBUG: Evaluating NuGet output for line:
Finished installing 'ruby' and dependencies - if errors not shown in console, none detected. Check log for errors if unsure.

That's not exactly the situation. I would explicitly install an old version and then just install the latest (let Chocolatey pick). I wonder if going from only a 32-bit URL to a 64-bit URL in the second install changes anything?

> choco install ruby -version 1.9.3.54500
> choco install ruby -force