Is there a simple way to change the origin point of a lot of objects at once? I have a piano keyboard, so there are 88 individual keys. Unfortunately, I left the origins in the centers of each key. As a result, I can't rotate them properly. I could go through each one and manually correct each key, but that would be a huge pain. Is there a way to set them all at once? (I only need to move the x location on each key, in case that makes a difference).
Select all your piano keys. 
Set your 3D cursor to the location where you want your point of rotation. 
Object -> Transform -> Origin To 3D Cursor


That will set the origin for all the piano keys at once.