Pervasive computing calls for suitable middleware and programming models to deal with large software systems dived in dynamic mobile network environments. Here we present the programming model of TOTA ("Tuples On The Air"), a novel middleware for supporting adaptive context-aware activities in pervasive computing scenarios. The key idea in TOTA is to rely on spatially distributed tuples, propagated across a network on the basis of application-specific rules, for both representing contextual information and supporting uncoupled interactions between application components. As shown with the help of a case study scenario, TOTA promotes a simple programming model and can effectively facilitate access to distributed information, navigation in complex networks, and achievement of complex coordination tasks in a fully distributed and adaptive way.