Google added this feature now in the "new spreadsheet format". This can be enabled for new documents like follows:
On "MyDrive" go to settings choose Editing and then "Try the new Google Sheets".
Please be aware that as of now not all features are complete, so treat it as a beta version.
One of the changes in this new spreadsheet is the possibility to define custom formulas in the conditional formatting option.
This formula would then allow the alternating coloring in the sheet (if applied to whole sheet):
=MOD(ROW(A2),2) < 1 Just for completeness: I'm using the new sheets now for quite some time and did not yet find a feature I was missing. While the custom formulas are very helpful - not only for alternating colors.
Select Conditional Formatting:
Create a custom Formula with Background Color and Range of Cells:
See the result:
