I created the visualization using D3.js. It's essentially a scatter plot in which each scene is represented by a dot. The scenes are arranged along the x-axis in the order they occur in the book, and are chronologically positioned along the y-axis. You can use the interactive version if you have a "modern" browser, i.e. recent versions of Firefox, Chrome, Opera and Safari. IE users will have to make do with the images in this post.
The main ideas I was interested in visualizing were what happened, when, and who was present. The when question is particularly interesting due to Wallace's use of Subsidised Time. It became clear as I was preparing the data that much of the book is set during the Year of the Depend Adult Undergarment, but I pressed on with the visualization anyway.
Mouse-over a scene's dot and a summary of the scene is displayed below the chart. Names of the characters present in the scene are highlighted in the legend to the right of the chart. You can also mouse-over a character's name in the legend, which will highlight those scenes in which the character makes an appearance.
Not all scenes can be pinned down to a particular date; for some only the year is known (in such cases the scene's dot is positioned at the start of the year). Some scenes have no obvious date so they're located at the bottom of the chart; the unspecified year.
For more info visit http://www.vislives.com/2011/12/infinite-jest-visualization.html
Source code available on GitHub https://gist.github.com/1291635