At 11 a.m. on a hot Tuesday in October, cars began to line up at a pair of tents pitched in a deserted stretch of downtown Los Angeles. At the first tent, Damian Diaz greeted every arrival with cold Topo Chicos and bright greetings in Spanish. He handed out sandwiches donated by a local shop, bagged-up snacks, and juice boxes; some families received books carefully sorted by reading level. Next, the cars pulled up to a second tent, where volunteers