The downside (there's always a downside) is that over the course of reading it I caught at least 3 factual errors. Granted, one I wouldn't have noticed if it hadn't come up in a recent round of pub trivia, but another was an obviously imbalanced chemical equation and the third was something any self-respecting geek should know.
And mistakes are pretty much a fatal flaw for what is essentially a trivia book.
Now saying one wrong thing (or three) doesn't make everything in the book wrong. However trivia, whether in a book or contest form, attracts people (myself included) who get caught up in the details and pride themselves on getting them right. I've been to more than a few trivia contests that have featured heated debates, either amongst teammates or with the quizmaster, over minutia. (The irony being that that trivia is, well, trivial and not worth heated argument) The attitude is summed up in a quote notably missing from The Geeks' Guide's quotable Futurama: "[Y]ou are technically correct – the best kind of correct!"
So if you're one of those people who will be bothered finding one or two errors in a bathroom reader (or not finding them, but knowing they're there) it's probably best to skip this one. But if you can overlook some minor mistakes to find out how to load a pair of dice, learn tongue twisters in foreign languages or discover a quick trick for dividing by 7 then it might be worth checking out - at least for those moments when you're on the can.
The Geeks' Guide to World Domination by Garth Sundem
Some of the entries, and some not in the book, can be read at the author's blog.