With Calc opened up, view the Styles and Formatting window (Format > Styles and Formatting)
Right click in the empty white space of that box and select “New”
Name the new cell style “odd”
Change the background color of the cell to a color of your desire
Click OK
Repeat step #2 and create a style called “even”
Change the background color to a different color of your choice
Click OK
Select the range of cells that you want to zebra strip
Click Format > Conditional Formating…
Change the values in that box to match these
The brains of this operation is the MOD(ROW();2)=0 and MOD(ROW();2)=1
To tweak the formating just edit the styles “odd” and “even”