It's 6.004, and it looks like they are still teaching it, which I was pleased to discover. Students are no longer asked to carry around the suitcase-sized breadboard "nerd kit" and they aren't using 74XX TTL chips any more. Now it's all done using simulators.

The name of the course is "Computation Structures", or, as MIT students would know it (since nearly everything at MIT is numbered, including buildings and departments), 6.004:

http://6004.mit.edu/

Sounds like http://www.nand2tetris.org/