Maria Droujkova has done some wonderful work creating math projects for young children. I've seen early drafts of the Moebius Noodles book, and it's exciting.
Her project is featured for one week at tippingbucket.org. She has to raise $6200 in that time. (If she doesn't, the donations aren't taken. The project has been up for 5 hours so far, and over $1200 has already been donated.)
Disclaimer: Maria is starting a publishing company, Delta Stream Media, which will be publishing my book, Playing With Math. Our projects are somewhat intertwined.