Here is a contraption that Ian and I made to keep Liam occupied during diaper changes. It is essentially a glorified magazine rack that I slip Liam's colourful books into so that they are held in place for him to look at.
You can see how interested he is in the firetrucks on this page. We decorated the wooden doweling with wooden zoo creatures that match the mirrors I made for his room. And look how cute he is in his diaper!!