Any book recommendations, for a gifted 8 year old boy, that gives a lot of useful knowledge about a wide variety of topics?

Wow, that made a lot more sense in my head. Let me try that another way...my son loves impressing us with all that he knows (which is a lot more than we typically give him credit for...especially my 19 year old daughter who is in college).

ie: the other night we were discussing spiders and he told us they typically have 8 eyes...the whole family (including me) got a strange look on our faces. Of course we googled it and he was right...asked him how he knew it and he said he didn't know.

So, since he loves gaining and giving knowledge, I'm looking for a book that might interest him and contains a lot of facts from a variety of topics.

Thanks.

TripleB

I understand what you are asking for - my son is similar in the sense that he knows and is fascinated by weird facts about weird things and has a strong recall of them. But, there is no single book that is going to help. You may need to get a bunch of books on each subject/topic that he might be interested in.
Amongst what we have, my DS likes his kid's encyclopedia, the Guinness book of world record and a few Ripley's believe it or not books for reading on all kinds of topics.
He also likes the books "The Way Things Work" and "The new Way Things Work" by David Macaulay - they are packed with a lot of "information" for him.

There are the TIME for Kids Big Book of ____ books, such as TIME for Kids BIG Book of Why: 1,001 Facts Kids Want to Know. I think they also have BIG Book of How, When, Who, etc.
National Geographic also has a "Big Book" series, like National Geographic Little Kids First Big Book of Why and 5,000 Awesome Facts (About Everything!).

We have shelves of these. :-) Great suggestions above. DS9 really likes the National Geographic books and has several. He also really enjoys the annual kid's almanacs and Guiness books. He has picked up some prior years of these at the library's used book sales.

We have a lot of these books at home (World Records, Amazing Facts, Big Books of Whatever, Kids Almanac, etc), and both kids enjoy reading them. They also like magazines like Ask and Muse, which provide a monthly dose of fun topics.

DS10 loves Randall Munroe's What If? book, and will most likely be getting his new one, Thing Explainer, for Christmas.

Have you considered a game like Trivial Pursuit?

I second the subscription to Muse. It's amazing how often DS10 will jump into a conversation at home or at school with some highly relevant but obscure factoid that he picked up from reading Muse.

We have a subscription to Muse, DS11 likes it a lot. DS also loves What If? by Randall Munroe. KnittingMama probably has a lot of the same books we have in our house

More mechanically focused, but a terrific set of options.

http://www.amazon.com/The-Things-Work-David-Macaulay/dp/0395428572

http://www.amazon.com/The-Way-We-Work-Getting/dp/0618233784/ref=pd_sim_14_1/186-5698144-5292660?ie=UTF8&dpID=51Ia5cxSfOL&dpSrc=sims&preST=_AC_UL160_SR120%2C160_&refRID=009SHPS80Y8SWTWXZSX6

http://www.amazon.com/Built-Last-David-Macaulay/dp/0547342403/ref=pd_sim_14_2?ie=UTF8&dpID=51OInYUSU8L&dpSrc=sims&preST=_AC_UL160_SR125%2C160_&refRID=1ER65SCKHFZBGJVBHKPH