A recent update to Google Calendar (in its web version) means that it now offers permanent links to every page. As Google Operating System points out, this means you can now use the browser back and forward buttons — which makes navigating much faster.
As well as being able to click the browser back and forward buttons, you can use the keyboard shortcuts (Alt plus the left and right arrow keys, or Backspace for back) to move around. Definitely useful as an addition to the existing Google Calendar keyboard shortcuts.
Google Calendar Permalinks [Google Operating System]