I've just finished reading The Da Vinci Code, which I started this past Tuesday. It didn't take my attention at first, as it seemed just like many other mystery stories, but after around 50 pages, I was hooked. I can't remember any other book which has captivated my interest so much.
As you may already know, this is a novel, so the story in it, as well as the characters, are all fiction. The story itself is well explained and full of surprises. But what makes the book interesting, IMHO, is that it's based on true facts: the scenarios, the pictures, the places, the people... most of them are real.
Of course, you shouldn't believe everything explained; it will require research on your side to decide what's real and what's not (and some things only depend on your faith). It's hard to split where the truth finishes and the fiction starts, which is probably a good aspect of the book, as it will raise your interest in some things you may have never thought about.
All I can say is that it has been an amazing read! I truly recommend it. For more information, just go to the official website linked above; I hope there are no spoilers, but the book will be more exciting if you know nothing beforehand ;-)