In one sense, a complete rewrite of human society, as people turn around and walk out of prison, marriage, job, or whatever it is in life they were tired of. In another sense -- nothing at all; this book has only the barest traces of plot. Sense of wonder, absolutely, in buckets. Characters, yes: we get the solipsistic explorer, the jovial-but-opaque sentient computer (nee Tibetan motorcycle repairman; reincarnation appears to interact oddly with technology), and a mess of associated folks. They're all reasonably solid and amusing to hang out with.
No story, though. This is a tromp through Rama, a flycycle picaresque across the Ringworld. It's yet another infinitely-extended geography of the American frontier (and I'm beginning to think it's my fault authors keep writing them; I keep being unsatisfied...). One might be intrigued by a whiff of non-human step-capable sentients, or worried by a few scenes about political dissent and terrorism; but this isn't a mystery or a thriller. It's a trip.