Dynamic Pivot Table

I do not have very much experience with pivot tables but I do know they can be very powerful.

I have created a simple table that right now will just sort by the clients via a pulldown menu on user page (so the program needs to be clean not accessing the pivot table directly). It works great but now I am being asked to also be able to sort via other options for each client. Each client has different potential other options based on who you select so I am a little overwhelmed.

I am always good at looking at examples and then hacking something together.

Can anyone point me to an example of this kind of product that I would download and dissect?