MARC -> BIBFRAME/RDA transitions
The library world will be making a transition to a linked data format over the next number of years. The Library of Congress is leading the way with BIBFRAME and RDA is a thing too.
This is going to require a lot of new infrastructure at the core of library systems. Maybe we could take the time to (over-)engineer them with version control + provenance for the metadata. And serve it up with Memento, so that we can query description at different points in time?