Frank,
I prefer functional to awesome. Your not certain what the string of numbers
do, so to understand you need to break down the formula as follows:-
Lets assume we are working with any date in March
1. Find the last day of the previous month- =A1-DAY(A1) returns 29/2/2008
2. Find out what day that was- =WEEKDAY(A1-DAY(A1)) returns 6 for Friday
3. Add the required amount of days
=CHOOSE(WEEKDAY(A1-DAY(A1)),13,12,11,10,9,8,14)
We know the middle bit evalustes to 6 and the Choose bit tells it to 'choose
the 6th element of that array of numbers which is 8
5. Add 8 days to 29/2 and you get the second saturday
So to make it work for the third monday we use exactly the same formula but
alter the array of numbers to 22,21,20,19,18,17,23
Mike