Open Book, conceived in a misguided attempt to bag the 'looks most like a real paper diary' prize in the AKTC. Technically, it's three-column, but I think of it more as a two-col. I mean, it's a book. You can't get much more two-col than a book.
(I know this sounds obvious, but please take bug reports, support requests etc. to email or the link above rather than here. There is a much higher chance of me seeing stuff if it goes through my own site.)
[excuse typo while tagging this. hopefully a mod will be along to delete it shortly]