1. A system for dynamic human workflow task assignment using business rules, comprising: a computer including a workflow process executing therein, wherein the workflow process generates tasks for assignment to human users; a plurality of tasks defined by the workflow process; an interface that allows for the plugin of one or more external business rules engines, wherein each of the external business rules engines specifies rules as to how one or more of the task should be processed or routed, according to patterns specified by the external business rules engine; and wherein during execution of the workflow process in executing a particular task, the system accesses any rules engines plugged into the interface, to determine the processing or routing of the particular task to the human users.