Word Nerd, by Susan Nielsen
We picked this book up at a children's book shop in Vancouver, BC, a few years ago, and I've finally read it. Rare for me, I even finished it in one day! Highly readable.
I loved the painfully awkward and uncomfortable Ambrose...who is deathly allergic to peanuts and always manages to say the worst possible (and often, honest) thing. Consequently, the only one who really likes to be around him is his mom. Because his dad died while his mom was pregnant, and Ambrose almost died because of his peanut allergy, his mom is obsessively overprotective.
When Ambrose crosses some school bullies who put a peanut into his sandwich, he and his mom decide that home schooling might be the best approach. He befriends Cosmo, a grumpy ex-con, ex-druggie son of his Greek landlords, and his life changes. They join a Scrabble club together, after much cajoling and conniving by Ambrose. (His mother has instructed him not to have any contact with Cosmo.) Soon Cosmo falls in love and Ambrose's life finally starts to get interesting.
In the quirky world of competitive Scrabble players, Ambrose finally feels at home.