Orient and Origin to Selected
Quickly manipulate the object origin.
A small Blender add-on for changing an object's origin and local orientation while in Edit Mode. To use Orient to Selected, switch to Local Space, select some geometry, and press Orient to Selected in the orientation dropdown. For Origin to Selected, go to Mesh -> Snap.
What's New
No changelog for this release.
It is perfect. Would have been even better if "Origin to Selected" was also available in the Snap pie menu (Shift-S).