As I've said before, I find the WWDC videos to be invaluable and I try watch all of them eventually. But there are a lot of them, and it can be hard to find what's relevant. And a lot of them I go back and watch again when I start working with a different part of a project.
So I've developed a trick, and I thought I'd share it with you all.
I go to the site where the videos are hosted and click on the "view all in iTunes button". From iTunes, I download all the slides (Click a track like "Essentials", then click "Slides" just above the list, and then click the "Get Tracks" button in the header).
I keep all the slides for WWDC 2010, 2011 and 2012 in subdirectories of a folder named "WWDC slides" in my Documents directory. It's indexed by Spotlight on my Mac.
From then on, when I'm working on a project, and I'm having trouble with something, or trying to remember something I might have seen, I open up that folder in Finder, and type the Class or Method names of the Classes I'm working with, and Spotlight will tell me the session names of the videos I might want to watch.
So, for example, if I type 'NSFetchRequest', the first result is "Session 214 - Core Data Best Practices" from WWDC2012. I type 'registerNib:', and I get "Session 125 - UITableView Changes, Tips, Tricks" from WWDC2011 (among others).
Then I just go to iTunes or the website, and I know which video to go watch.
It's a handy trick (and I use it to search through all my eBooks on programming, as well), and when I've recommended specific videos to people, I've had several of them ask me how I keep the videos straight.
So hopefully it's useful to some of you.