For those of you that are heavy users of Mission Control Spaces, you might like the open source app WhichSpace. It does one simple thing well: it displays the current Mission Control Space Number on the Mac menubar.
And then if you are also a Keyboard Maestro user…
With the help of the WhichSpace author, George Christou, I created a macro named Return to Previous Mission Control Space Macro. It is used to return to the previously displayed Mission Control Space. For example, if Space 5 is visible, ^2 is used to move to Space 2, ^Return will return to Space 5. Since ^Return again will return to Space 2, this macro makes it easy to toggle between two nonadjacent Mission Control Spaces.