Some more math and reading links, continuing on from yesterday's post:
Dr. Labush's Links to Learning connects you to online games (I highly recommend The Fruit Game and FEMA for Kids Disaster Math), learning units, worksheets (if you like that sort of thing), etc. from kindergarten up to college-level math. The home page also has links for history, science, animals, national parks, etc.
Carol Hurst's Children's Literature Site. The Math section is a bit of a stretch imho, but there is an extensive list of curriculum subjects which each lead to lists of suggested books, both fiction and non-fiction, on the elementary school level for each subject. Each book has ordering information and a one or two sentence review.
I'd also like to add a plug for The Queen's Gambit by Walter Tevis. It's a coming-of-age story about a female chess prodigy, following her from her first chess game at the age of 8 to international level play at 16. It's a real page-turner and would be a terrific gift for a female math whiz--a protagonist she could really identify with. DH, who mostly like spy thrillers, also rearranged his lunch schedule so he could hear this novel serialized on Chapter A Day on Wisconsin Public Radio, so it will appeal to boys as well as girls.