This book is HUGE, and challenging, and I'll have to pay some overdue-book library fines for it. Oh well.
Let me put it into hard data for you: the story is 981 pages long, and we're talking about some standard-size, 43-lines long, size 12 text here. And then you have 98 pages' worth of endnotes (388 endnotes total). Which makes for a 23.5 cm (9.5") long, 15 cm (6") wide, and 5 cm (2") thick brick - and that's with a soft cover.
Now, about the story itself: it's a nonlinear narration that follows a bunch of characters. These include a competitive-junior-tennis player and total pothead who attends this tennis academy his parents have founded, his older brother, his older brother's super pretty ex-girlfriend, an ex-Demerol addict dude with a huge head who now works at a halfway house down the hill from the tennis academy, and a superviolent Québec separatist terrorist cell descriptively named Les Assassins en Fauteuils Roulants (The Wheelchaired Assassins). Plus a bunch of other characters. Who are all, in twisted and non-obvious and often surprising ways, interconnected.
This novel (published in 1996, hey look at that right after the last Québec Referendum; this might explain why Québec Separatism is such a huge thing in this book) takes place in the future - that is, at about this point in time. However, I don't know that for sure since a new time-naming system has been conceived to help keep the North American economy strong; years are sponsored by different products. So you get the Year of the Trial-Size Dove Bar. Or the Year of the Whopper. Or the Year of the Depend Adult Undergarment (which is the year of the story). Which is rather confusing until, after a few hundred pages or so, a convenient list of the years' chronological order just appears.
Ok, so what else... A huge northeastern chunk of the United States and of eastern Canada (bye-bye New Brunswick and southeastern Québec!) is called the great Concavity. You see, instead of filling up landfills everywhere in north america, the O.N.A.N. just launches its garbage (on prime numbered days only!) into that region, the Concavity. Which is the site of so-called "annular fission", a weird thing that removes toxic waste from the environment to provide literally clean energy to the ONANite countries. So essentially what happens is that in the early part of the month the Concavity is this teratogenic, carcinogenic, toxic wasteland, and in the late part of the month it becomes this super lush and overgrown jungle full of feral hamsters and "insects of Volkswagen size". You know what? I think this means it's a dystopian novel. Because seriously, wtf?
The thing about this novel, though, is that the entire story feels like a giant foreshadowing of this dark, looming and terribly awful thing that's going to happen - and after the first chapter you know something really messed up happened - and yet it never tells you what happened. Or really, what will happen; the novel ends on a completely unresolved note (um, spoiler alert I guess?). It's a great read, though; a challenging one, but even without resolution I think it's worth it.
On a final note: although it didn't take me 100 years to read Infinite Jest (yes, I'm bragging right now), it did take me almost two weeks. I wasn't reading anything else. IT'S JUST SO HUGE!