Two recent sacred music projects by NLM contributor and friend-of-the-Cafe Peter Kwasniewski bear repeating here.
The first is the full-color facsimile edition of the 1903 Cantus Mariales. This reproduction contains 50 Marian chants for use throughout the liturgical year. Prof. Kwasniewski also produced several recordings of chants from the collection, with (beautiful!) harp accompaniment.
You can find the rest of the videos at the New Liturgical Movement.