The ability to calculate a date. For example, X days in the future/past from the date the action is run. Similar to what Plusthis provides.

This is particularly useful for setting to create 'contact specific offer deadlines' for anyone who proceeds through a workflow.

These Dates could then be saved in custom [date ]fields. The idea being one final update to the existing countdown timers feature... Which could then count down to any of the existing options... OR use a date written in a custom [date] fields on a contacts record where a calculated date has been saved..