beyond windows task manager

The Windows Task Manager provides very minimal information about what my
operating system is doing. How can I get more detailed information about my
system performance? I have no specific reason for wanting this information,
but I am just fascinated by operating systems . For example, if I want to
know all of the threads that are inside a given process, I don't think I can
get that through the Windows task manager. As another example, I would like
to know how my threads are being scheduled...round robin, first come first
serve, shortest job first, etc...and perhaps play around with the scheduler
(yes I know that is probably quite dangerous).