First, I dug a hole.

Then, I cut a post:

Then I figured out how big my board needed to be:

Then I marked my holes.

Then I drilled!

Then I mounted my hinges:

Then I mounted the board onto the post and hinges:

Then I stuck it in the ground and poured in the quick-crete:

Then I painted the board while I waited on the concrete to dry:

Then I mounted my hose roller thing!

And now I have a hose roller that turns to face either the side of the house, where I often need it—

—or the front of the house, where I often need it:

The only thing left to do is run to Home Despot and grab a coupling to stick two feeder hoses (I have another one) together so that there’s enough hose to let it turn more easily.
I had originally planned to do this with a piece of chain-link fencepost and a hinge in the middle of the board to let it turn nearly 360º, but the fenceposts were waaaaaaay more expensive than I anticipated.