Can I use conditional formatting ?

Hilite the cells (in your case A1:A50), and click Format > Conditional Formatting. In Condition 1's first drop down box, choose "Cell Value Is". In the next field choose "equal to", and in the third field type ="Sunday". Then click the Format button, click the Patterns tab, and choose the gray color you want to have those cells shaded.

Tom Urtis

Thanks!!!