the Square Note chant app for my Android smartphone which I mentioned here; the icon appears above. I think it is more than worth the $2.99 I spent; in fact, this is the first app this tech cheapskate has spent any money on.
It has all the propers for the liturgical year, both NO and EF. It has all the ordinaries and many of the other chants we use throughout the year (Stabat Mater, Adoro Te Devote, Salve Regina, etc.). Although I do not believe Kathy would want you to do this on any regular basis, it can be a source of last resort when you forget to bring some or all of your music.
The only downside, and it isn't much of one, is that the app plays back midi-sounding files for the pieces instead of the voices on Corpus Christi Watershed et al. It plays them along with the notes flashing if you press the screen at the beginning or in any other section. I recommend against how it runs through, say, the Gloria Patri, however; that staccato is exactly what Kathy doesn't want.
Perhaps best of all, each app download benefits its creators, the Oblates of St. Joseph in the United States. It's available for both Android and iPhone.