complex financial maths problem

[gaurav...@gmail.com]

Im looking for a complex financial maths problem?
Description

1) It should be time consuming.
Say I submit the problem at night, the computational period on
Mainframe Server or any powerful machine is around 3-10+ hours.

2) Every Finance Manager is looking for an answer to such a problem (
Its a day-to-day or common problem)

References to web-sites providing information would be great !!!!
Thanks in advance.