Maybe an “intermediate” CSS course would be an easier target? Now, offhand I can’t say I know what you cover under the “basics” umbrella, but I imagine its floated layouts, positioning runes, getting the most out of background images rather then gutting graphics up, and the like? Maybe getting into spites / background image rollovers but not much more complex?

To me the next step from there would be a combination of more complex positioning cases [using resetting origin then using abs. positioning], some of the negative margin based column techniques, using negative margins in general to overlap elements .. and then starting into more interactive concepts and how you’d use CSS as a part of something bigger – start with gratuitous use of :hover and then go using JS to swap classes [vs. setting style directly]. And finish off with some other “goodies” like trying to get transparency working, rounded corners, generated content, etc.