The second blog is http://ivansnumberblog.tumblr.com. Ivan is on a mission to convince the world that numbers and math problems are fascinating. In fact, Ivan's blog apparently preceded Daphne's, and one senses a direct rivalry between the two.
Take a look. Bring along a friend, preferably a young one, who loves words or numbers.
* In the interests of truth in advertising, I hereby disclose that my relationship to these blogs is somewhat closer that having "stumbled" on them.