A handy little pro tip for Mac OSX users – scenario: you have a Finder window open to a certain directory and you want to open another Finder window to the same directory, perhaps to put side by side with the current Finder window.
Just do this:
Press cmd + ctrl + o in Finder without any folders or files selected in that window.
Or if you do have a folder selected, cmd + ctrl + o will open a new Finder window into that selected folder.
Neat!