A co-worker sent out this simple Tetris implimentation in Javascript. (Using JQuery.)
From there (reading the source code) I ended up on wikipedia reading about the Tetris Effect and Tetrominos (which I’ve never spelled correctly before). Tetris even has its own category on Wikipedia. I should probably read up on how wikipedia categories work before I say this, but it seems like a fairly incomplete list.
Anyway, from the Tetris Effect page, I ended up reading an old Wired article titled This is your Brain on Tetris.