Today's XKCD, "Click and Drag," is a triumph. It's a tribute to House of Leaves, and it treats the punchline as a window to a ginormous, explorable world that you can see by clicking and dragging. Dan Catt puts the artwork at 46 feet wide, assuming it is printed at 300dpi. It's full of Munrovian sly humor and sight gags, and has its own underground civilization. It's not like any other thing I've seen.
If you want to mouse around in a zoomable version of the map, see this mashup. If (when) Randall offers this for sale as a poster, I may have to throw away some furniture to make room for it.