I am giving a lecture on Postkinov towers and I want to teach the students a lesson :). These students have seen local coefficients, spectral sequences and cohomology operations at the level of mosher and tangora.
Some I ideas I had were, in view of their knowledge of local coefficients, deal with the case where the tower is constructed on a nonsimply connected space, as given in Robison's paper.
The other idea I had was to present what I learned from doing the exercises in Davis and Kirk's algebraic topology book on Postkinov Towers. Another idea is to do it from the point of view of obstruction theory, as done in Spanier.
Do you have any suggestions or alternate expositions you know of, or exceptionally good ways of motivating this topic? The best answer will be given a bounty of 50 points.