Design Patterns discussion

[<conradwt AT runbox.com>]

Hi,  I have a problem dealing with task prioritization (i.e. allocating tasks 
to agents that are stored in a database based a computed priority value).  
The agents will initiate the retrieval of getting a task from the database 
and they should get the one that has the highest computed priority value 
based on the type of tasks that they can work on.  Next, this priority value 
can be change based on the time that a certain task needs to be completed.  
For example,  if a task is due in 4 hours that's in the database (i.e. not 
assigned to an agent) and two hours have passed, then it's priority will 
increase.  This has a rippling effect because as time changes on the hour 
boundary, the database must recompute the task's priority value.  Thus, I was 
wondering, are there any patterns that would assist me in designing and 
developing a clean solution?

Thanks in advance,

-Conrad