By coincidence, my second book in a row built around taking a big idea as far as it will go. Drew Magary's The Postmortal pulled off that trick very nicely; Helen DeWitt's Lightning Rods did not.
DeWitt's big idea is this: In a lot of large companies, the hard-driving alpha males who hold most of the executive spots are, in part because of the same hard-driving alphaness that makes them top executives, among the employees most prone to commit acts of sexual harassment. So what if you could defuse their levels of sexual tension by providing them with an on-the-job way to get their jollies?
Thus, the "lightning rods" are created; they're women who are legitimately employed by a company as secretaries or IT people or whatever, but who agree, for a significant bonus in pay, to provide (and the premise really is this crude) a convenient hole when a guy needs something to fuck. The gimmick is that the lightning rod service is to be entirely anonymous. The company agrees to turn over the majority of its staffing to the lightning rod agency, and thus doesn't know which of its employees are also serving as lightning rods; and the sexual encounters happen through a hole in the wall that allows each participant to see only the lower half of the other's body.
There is an occasional clever or amusing extrapolation from this idea (how do you maintain the program's anonymity at a small midwestern company when its first black female employee wants in on the lightning rod pay bonus?), but mostly the book is cheap, smirky, juvenile smut.