Try the following...

1) Select your cell for Data Validation

2) Data > Validation > Settings > Allow > Custom > Formula

3) Enter the following formula:

=(WEEKDAY(A1,2)<6)*(1-ISNUMBER(MATCH(A1,C1:C10,0)))

...where A1 is your Data Validation cell, and C1:C10 contains your list of holidays.

Hope this helps!