Here's a set of Eagle files for the benefit of my ECE4450: Analog Circuits for Music Synthesis studnets; hopefully other folks will find them helpful as well.
To use acms_project_starter_template, I recommend copying the schematic file and giving it a new filename and deleting the parts you don't need, but not copying the board file. Official tangible waves modules use surface mount parts for manufacturability and to keep the size small. Since we're using through-hole parts, we need more space, so I made it three Tangible Waves module units wide (75 millimeters). You can try making this 50 millimeters wide instead if you have a small circuit (change the width to 1.9685 inches and delete the two rightmost mounting holes and then scoot the headers over).
To use acms_project_starter_template, I recommend copying the schematic file and giving it a new filename and deleting the parts you don't need, but not copying the board file. The board file shows where to put mounting holes (size 0.12587425 = 3.2 mm), but otherwise isn't too useful, since once you start adding your own parts, Eagle will just plunk them down one after another in a straight line going downward. If you place your parts on the schematic first and then tell Eagle to make the PCB, the parts will appear in a nice convenient grid pattern on the side of the PCB.
ota_upgraded.lbr and synthdiy_upgraded.lbr are librraries I found elsewhere that didn't want to open in the newest version of Eagle; apparently the name for layer 88 got scrabled as part of the input process. I just changed the layer name to "weird" to get something that would import without error.
The devices in the aaronXXXX.lbr libraries all have the suffix _AARON; I did that so I can find my custom devices quickly.
The capacitors in the eagle library have a little capacitor symbol on the PCB footprint, and have the cap value outside. I prefer to put the cap value inside the symbol footprint, so I made aaroncap.lbr, which has some capacitor footprints with the cap symbol removed and the value placed inside the capacitor.
aaronlibrary.lbr has an oval PCB pad with a little X for the schematic symbol (IOPAD_AARON), a jack symbol on the schematic for off-board jacks where the PCB has a circular pad for the signal and a square pad for the ground (OFFBOARD2JACKALT_AARON), and symbols for the SSM2210 and SSM2220 matched transistor pairs.
I made aaronpot.lbr to handle some potentiometers where I couldn't find a built-in Eagle symbol that exactly matched it. I can't remember exactly what I made it for.