I picked up some great things (levels tweaking, using the measure tool and Image>Rotate>Arbitrary to straighten images) and Jenine's working her way through the video lessons now. She just described it as "fun and interesting" in a surprised kind of way. I don't think anyone imagines that there's a fun way to learn the cool things Photoshop can do, but Deke's done it. We only have Photoshop 7, not CS, but 90% of what he describes applies just as much to older Photoshops.
Now, to tell her to go to sleep so I can read some more of the book