Dan Ingalls: Object-Oriented Programming - 1989 [video]
video.google.com
video.google.com
Its neat to see this posted here. I'm a self educated hacker and years back this video is what finally helped me grok OOP. At the time I could copy and paste code, but had little grasp of the ideas behind it. Ingalls' "Hospital as an object" analogy is what made the model click.
It is a beautiful video. I also recommend to everyone who's interested in high quality material about OOP to read [1].
[1] Smalltalk, Objects, and Design by Chamond Liu http://claritycomputing.com/book_sod.html