A portable cable organizer which is setup as an easy print-in-place and includes a knob on the side for conveniently winding up the cable when you're ready to pack it away.

This model is an easy print that requires no supports, and three different sizes are provided to accommodate cables of different lengths.  If you're not sure which to choose, I'd recommend starting with the “medium” size.  

After printing, you'll want to place the cable within the groove at its halfway point, close the lid (which is intentionally designed to close tightly), wind up the cord clockwise using the handle, and then extend by simply grabbing the cable by both ends.

Update 2023-09-06:

Alternative smooth-sided versions of all three sizes have now been added, and also the handle design was slightly adjusted to add a small fillet and chamfer to decrease the bridge distance.  Here's a close-up picture of the updated handle on the knurled and smooth-sided versions: