I am using Ubuntu 14.04 LTS and I cannot find workspaces. I have done searches in the Dash for it, I have tried 'sudo apt-get install workspaces' in a terminal. All without success, help required!
Try to go to "Appearance" -> Behavior tab and click enable workspaces. You can find it more detailed here: How do I turn on workspaces? (Why do I only have one workspace?)