Seen all over, but most recently at hils.
Pick a paragraph (or any passage less than 500 words) from any fanfic I've written, and comment to this post with that selection [Note: Please include the title/fandom & a link wouldn't be bad if it's something older]. I will then give you a DVD commentary on that snippet: what I was thinking when I wrote it, why I wrote it in the first place, what's going on in the character's heads, why I chose certain words, what this moment means in the context of the rest of the fic, lots of awful puns, and anything else that you'd expect to find on a DVD commentary track.
My newest fic is on the sidebar, older stuff posted on LJ is listed here, and then there's my archive, Tales From the Darkwood. Or,there's always the 'fic' tag.