The Getbundles Textmate bundle refuses to work under Ruby 1.9.2. You will see a series of errors in the log file which can be seen by going to Bundles -> GetBundles -> Open Log File.
If Bundles -> GetBundles -> Get Bundles is not working for you, you will probably see something similar to this in your log file:
syntax error, unexpected ':', expecting keyword_then or ',' or ';' or '\n'
To fix this problem and to make life easier in general, I would suggest downloading RVM (Ruby Version Manager). You can find install instructions here. Once installed, you only have to run a few commands to fix the GetBundles issue.
rvm install 1.8.6
rvm use 1.8.6 --default
These commands will install Ruby version 1.8.6 and set it to your system default. If you try Bundles -> GetBundles -> Get Bundles again, it may work for you, or you might get another set of errors similar to:
/Applications/TextMate.app/Contents/SharedSupport/Support/lib/osx/plist.bundle: dlopen(/Applications/TextMate.app/Contents/SharedSupport/Support/lib/osx/plist.bundle, 9): no suitable image found. Did find: (LoadError)
To fix these errors, only three commands are needed:
svn export http://svn.textmate.org/trunk/Support/lib/osx/keychain.bundle
svn export http://svn.textmate.org/trunk/Support/lib/osx/plist.bundle
- Essential TextMate Shortcuts, Tips and Techniques (net.tutsplus.com)