"Life, the Universe and Everything" by Douglas Adams
OK, the third book in the series. Not going to lie, this would have killed as a video game; in the book medium, it reads, well, as anything that Adams has written publicly. It is full of unexpected turns of events that seem to have no relation to each other, but are ideas quickly thrown together with a pretense of a coherent (or incoherent) plot.
Overall, the main ideas revolve around Krikkit, the planet that wanted to kill the universe. In the end, it didn't, so we have that going for us. Robots, immortal serial insulters, time travel (why wouldn't characters travel through time?) and the main character suddenly flying. Also, an AI that plotted the whole thing and set up Krikkit as the executors.
At least now I can start catching all the wild references to this book in pop culture!