I pulled this formula from the web somewhere - it returns the tab name
=MID(CELL("filename"), FIND("]",CELL("filename"))+1,
LEN(CELL("filename"))-FIND("]", CELL("filename")))

But if I copy it to various sheets, F9 does not recalculate it correctly. I
actually have to go to each sheet and do Shift+F9 or F9 to make it display
the right name. Even if my workbook is set to Automatic Calculation, this
cell will not update until I go to that tab and F9 it.

Any advice?