Well it would be good if every episode would have a topic here and a link on youtube to that topic.
I'm pretty sure that has been discussed(What became of it I'm not sure.), everything you are seeing around you is pretty new. You should check out the annotation player(if you haven't) it really makes it easy to find something specific later and jump around and refresh old info.
ref. youtube comments, there was some shitty comments, and it isn't possible to have a good conversation about any subject (especially for others to reference later) in a youtube comment thread.
(back on topic)
I can't really point at a specific episode I like more, but those I expected to be dry and or boring because of the subject but never are, those are pretty good.
I also like the evergreen episodes where Casey starts from scratch on something different, as I'am/was learning (writing out the code and trying to understand it)those were really nice as a break where I didn't need to think in relation to the rest of the code base.
ex. the asset packer/builder episodes and the compression episodes.
Oh and of course any episode where Casey just remakes and explains a function I never knew how worked, but I had wondered.
TL:DR; To someone that wants to know how everything works or can work its all interesting.