Do you know that Excel cant …

• Refer to other sheets in conditional formating. You can only refer to the sheet where conditional formating is being applied.
• Refer to closed workbooks using indirect() function. It will return #Ref error when you refer to other workbooks in indirect function. By the way if you want to refer to some other workbook in your excel sheet, you can for example write,
  ='C:\something\someotherthing\morethings\mysheets\
[book1.xls]'sheet1!a1
• Name 2 workbooks with same value while they both are open.

Actually no easy workarounds exist for these, but as far as I know you can overcome second point by implementing VBA versions of indirect like pull() defined here and indirect.ext() here. Happy excelling 🙂