My good friend Srikanth Srinivasan is a Project Manager whom Microsoft will definitely want to hire as evangelist. He uses the functionality of Excel to great extent and made it ubiquitous.
The following code was for him, which highlights the ranges that are not protected in Excel sheet
Dim oWS As Worksheet
Dim oRng As AllowEditRange
Set oWS = ActiveSheet
For Each oRng In oWS.Protection.AllowEditRanges
oRng.Range.Interior.ColorIndex = 35