In this article, we examine the affordances of polylingual and polycultural learning ecologies in expanding the linguistic repertoires of children, particularly young Dual Language Learners. In contrast to settings that promote the development of English and academic language at the expense of maintaining and developing home language, we argue that the social organization of learning should privilege participation in dynamic, hybrid literacy practices. Children are often more likely to experiment with English and academic genres, while also taking on powerful identities as learners and language users, when formal and informal modes of communication are leveraged, multimodality and language-crossing encouraged and the use of both home and academic vernaculars promoted within a context that values social relationships and the playful imagination. We argue that children's literacy practices develop in particular social and "located" relationships, and we examine one such after-school setting designed with these principles in mind, the long-standing UC Links/Las Redes partnership, where home languages and intercultural experiences are unmarked and necessarily integral to participating in the shared practices of the community. We highlight the affordance of one common practice of the community, children s communication with the mythical cyber wizard, El Maga (sic), and the ways this practice strategically draws on students full linguistic toolkits in order to invite them to integrate modes and genres of communication that challenge the divide between everyday and school-based literacies, stretching children beyond their current levels of literacy development. (Contains 3 notes and 10 figures.)