As part of the Berkeley Webcast project, a pair of presentations by Alan Kay (of Smalltalk fame) is available.  The presentation is from the early 1980s and discusses the development of user interface design from the 1960s onward.  If you ware into computer history at all, these are very interesting.

Part 1

Part 2

The entirity of CS61A is available in podcast format if it is easier to access that way.