I'd appreciate a summary of this 23 minute long audio recording ;)

It's a summary of the court's opinion and reasoning (and dissenting opinion) in the https://en.wikipedia.org/wiki/District_of_Columbia_v._Heller supreme court case, as to the constitutionality of DC's handgun restrictions at the time, in light of the second amendment. Worth a listen if you've any interest in how we regulate gun ownership, IMO.

If you use javascriptlets like:

    javascript:document.getElementsByTagName("video")[0].playbackRate=2

This actually works in chrome, to speed up the audio playback, if you're short on time.

I added the title, but I wouldnt do it justice, Scalia gives a fantastic overview of what the militia is in the first few minutes.

You can skip the recording and read the ruling itself. It is fairly short and there is nothing in it that is difficult to understand.

When was this?

I assume shortly after the supreme court vote on this case - June 26th, 2008. Perhaps the same day.