Long time in the tech field. More a Business Systems Analyst most times than a developer, but I wear both hats.
Things I have oodles of knowledge about:
Warehouse Management/Inventory Control
CRM(Microsoft Dynamics, SugarCRM, quite a few different ERP's)
Lots about Roofing and Printing
Rapid Learning Techniques
My preferred methodology is submergence aka out the airplane with silk and thread. Something very zen about having no f'n clue what you're doing, but knowing you will be skilled with it in a few weeks.