So you finally finished Infinite Jest. Wait, you haven't? Well consider this an incentive1; the Infinite Atlas, with the help of Google Maps, will let you discover and explore the seemingly endless locales of the novel.
The wealth of information the Infinite Atlas provides is staggering. It indexes locations of note not only in Boston, not only in the O.N.A.N., but across the entire world, indicating which are real, which are fictional, and which are approximated. Beyond that, you can restrict the visible points to specific story-lines or even specific characters (down to Don Gately's corpulent mother). It's also the best visualisation of the Great Concavity/Convexity around. Believe me, I've looked. It also gives fans a chance to upload their own pictures of the locations, so this is only going to get better.
As a proud guy-who-has-actually-read-Infinite-Jest, I can't really recommend the Infinite Atlas to anyone in the process of reading because you already have enough to soak in. But for anyone who's read it (or who has given up on pretending they will someday) it's an amazing resource. It's a wonderful look into Wallace's crazily complex world, and yet another reason to buckle down and finally tackle the beast, so get to it. [Infinite Atlas Thanks, Matt!]
1. You know, other than "having read what is quite possibly the best novel written in the past 20 years."
2. And all the footnotes too.
3. And the footnotes' footnotes.