No, I am checking my emails (it was in 2012), and all the links are broken.

however I could dig out the references to it. Apparently it was a course by Prof. Alex Aiken and karpathy was a TA.

This repository seems to be a future version of the same course. https://github.com/gboduljak/stanford-compilers-coursework

Edit: found the videos from the course on the archive https://archive.org/details/academictorrents_e31e54905c7b266...

Ah yes, I remember this one. Very challenging indeed. Thanks!