Pivot Calculated Item

[Cat]

I would like to do is create a calculated item that would
give me the second largest value of a field using the
large function. (i.e. to hopefully throw out the max value
just it case it was a fluke and use the 2nd max instead).

However, when I go into the pivot table toolbar and select
Pivot Table then Formulas, the calculated item option is
grayed out and I cannot select it. I did notice the help
said you could not do a calculated item on a grouped
field. Thus I calculated month in my actually data and
put the month field in for my row heading (instead of just
grouping the date field by month).

How do I create a calculated item?

I have a pivot table set up to summarize various item

My data is daily readings of A, B, and C for multiple
points (1,2,3...). I have the following column headings

Month Date Point A B C

In my pivot table I have the following rows for each month
using the standard values you can choose in layout.

1 2 3 4
Month 1
Average of A x x x x
Max of B x x x x
Average of C x x x x
Month 2
Average of A x x x x
Max of B x x x x
Average of C x x x x

These rows are listed grouped over each month and then
summarized over the entire time span in the total.

How can I replace Max of B with =large(B,2)?

I would also like to do something similar with a
calculated item in order to count occurances of B over a
certain value for a given month.

Thanks

Catherine