I haven't read the book, but a couple of weeks ago I watched the Da Vinvi Code movie and found it surprisingly enjoyable.
It is - of course - 100% hokum, but sometimes that is what I want; and it kept my attention and interest throughout (not easy to do). So I went on to watch the follow-up Angels and Demons (2009), and enjoyed it just as much.
I had heard all sorts of bad things, indeed nothing-but bad things, about the Da Vinci Code; but the basic plot idea is a solid one (and it is reused in the follow-up): an academic chap who is an expert in decoding symbols follows a 'treasure hunt' trail of clues against the clock - because only by solving the clues in sequence can the trail be followed - each clue leads onto the next.
There is a lot about religion, and specifically Christianity; and initially both films seem to be very anti-Catholic. But in the end it turns out that the RCC has goodies as well as baddies, and that a lot of the damning perspectives come from unreliable witnesses - evil characters. So the anti-Christian, debunking perspectives of the first part of the movie are, to a considerable extent, contradicted and undone by its later parts.
Something similar applies to Angels and Demons - many of the plot twists favour the Vatican perspective.
The DVC reminded me of some thirty years ago, when I was 'targeted' for conversion by Opus Dei. I had a colleague/ friend who was a member lived in one of their houses - and one (Sunday?) evening I got a phonecall, inviting me around; on arrival, to my surprise, I was shown to a little cinema and left alone to watch a movie about the founder and purposes of OD. It seemed a rather clumsy and inept gesture - although the propaganda film was fairly interesting. [Erroneous passage deleted.]
The appeal of OD seemed to be due to a combination of philosophical coherence with evangelical energy backed-up by a military organisation and attitude; a modern medievalism, technocratic monasticism...
My impression of British OD (as I recall) was very un-sinister and indeed un-glamorous - their HQ was dark and cramped, and with a school-dinners/ cooked-cabbage kind of atmosphere. All very different from the glamorous-opulent-powerful depiction of the Da Vinci Code.
Anyway, having heard nothing but Bad Things about the DVC - including its movie; I was pleasantly surprised by how entertaining and stimulating it turned-out to be. I shall continue on to watch the third movie of the series, which was released recently.