If you read the three days of Lang.NET posts I did last month and wondered "Man, I wish I could've seen...", fret no more.
My personal favorites:
- http://langnetsymposium.com/talks/2-10%20-%20remotion%20Mixins%20-%20Stefan%20Wenig%20and%20Fabian%20Schmied%20-%20rubicon.html (You have to watch this one, just watch the intro even if you're not a C# guy or interested in mixins in the slightest; just get to the part where they talk about the sign--you'll know what I mean when you get there. You can hear us laughing in the background--easily the funniest moment of the 3 days.)
Of course the other presentations are good, but each of these had a moment in them when I said, "Hmm...."