OO3: Conditional row coloring

Scenario: 3 alternate colors

Step 1:
Modify (right click \ Modify) existing style or create new style
Example: create style "RedBgnd", "YellowBgnd" and so on

Step 2:
Select worksheet
Menu: Format \ Conditional Formatting
Condition 1:
- change "Cell value" to "Formula is"
- enter formula: MOD(ROW();3)=2
- select "Cell Style"
Repeat to assign another style(s) to Condition 2 and so on

Source:
[Solved] Background Color Alternating Row Fill
http://user.services.openoffice.org/en/forum/viewtopic.php?f=9&t=8716