OpenWizardry is the concept of using a software assistant, one of the OpenWizardAssistants, to perform a lower-level task while keeping the interfaces and code accessible and perhaps even customizable. The Programmer becomes the wizard. The software is merely the wizard's assistant. (Watch out! we may end up with too many brooms!)
Consider an ordinary software wizard that helps you configure and install a package. There may be several configuration files and elements that need to be modified. Ordinary wizard programs take the attitude, "I'm the wizard. I'll do it all for you and you don't have to worry about the details and you don't need to know how it is done".
A Wizard's Assistant program would still carry out the wishes of the wizard, but at the same time would make visible or at least available and accessible to the wizard all of the interfaces, code, low-level commands the assistant uses to perform the task. The wizard's assistant would tell you what you want to know about as much as you care to know about and keep mum about details you don't care about at the moment.
The idea of OpenWizardry came to mind after reading TheDumbingDownOfProgramming by EllenUllman.