My organisation has a number of software systems, most of which
require the ability to manage tasks for interactive users.

Characteristics of tasks:
- Name and description
- Creation time, creator
- Requested commencement time
- Completion deadline
- Task or event which resulted in this task being defined
- Individual or group responsible for completing task
- Work context in which this task is relevant
- Actions to take if the task is not completed in time (e.g.
reschedule, reassign, alert, etc)

I am looking for a server component or engine which can act as the
central repository for the tasks, and perhaps can perform the defined
actions when tasks become overdue. Because the engine would serve as a
task management or scheduling hub for a number of software systems, it
would need to offer a flexible integration mechanism such as web
service or messaging interfaces.

This seems like it must be a very standard problem, which has been
solved well by any number of vendors. However, I've become entangled
in the jungle of BPM and workflow engines, groupware, enterprise
scheduling and so on, most of which seem a little too large and
complex for the task at hand. Searching for scheduling components
results in a list of nice GUI controls, which are great for the front
end but don't solve my core problem.

My question:
- is there an established name for the kind of software component I am
looking for? if so, what is it, and what are the names of two leading
products running on the Microsoft platform?
- am I starting to reach the point where it would be advisable to
consider a complex workflow engine like K2.net or Skelta .NET???

Answers indicating that the researcher has an in-depth knowledge of
this field may well result in follow-up questions.