Lots of science ideas from Bright Minds (I looked in 7-10 year old age group)http://www.brightminds.co.uk/
sorry, you asked for books.
The Phantom Tolbooth:
There’s no sneakier way to tap into a kid’s curiosity about math than with The Phantom Tollbooth, by Norton Juster. This classic children’s novel takes readers on a mythical journey of Milo and his “watchdog,” Tock. The book touches on a variety of mathematic topics — from infinity to three-dimensional shapes. Bonus: there’s an equal emphasis on language, including idioms and puns. It’s bound to be a homerun for any young reader. Oh, and 2011 is the 50th anniversary of this classic. (Ages 10 and up) (From www.mathsforgrownups.com
1089 and All That: A Journey into Mathematics [Paperback]
David Acheson (Author)