Google periodically has visitors who come in and give talks on various subjects (a lot like the Nelson Series, but without a yearly theme, though most of them are CS-ey in some way). I have just found out that many of these are subsequently posted to Google Video so other people can see them, too. They’re pretty great, if ever you have a yen for intellectual discourse.
In particular, I’m quite impressed with Chris Spurgeon’s talk about great achievements in map-making and navigation.