I'll start with one of my favorite mural projects.  Because the client was on a tight budget, we found a very good way to work together on this one, helped by the fact that we both understood the process and could picture the end result.  She gave me a clear description of how she wanted illustrations from a favorite children's book adapted for her kids' room, I drew an outline of the illustration, she put that on a transparency which she projected onto the wall and traced (with the tree reaching up to the ceiling in one corner of the room), and I painted what you see below.  She figured out how to place the projector to minimize distortion on each wall, had a hand in an art project she wouldn't have wanted to tackle on her own, and saved money by doing some of the work.  I was happy to have her involved and didn't mind shaving a few hours of my time from the project.  The only downside was that they have since moved to a new home....