We present TOTA ("Tuples On The Air"), a novel middleware for supporting adaptive context-aware application in dynamic network scenarios. The key idea in TOTA is to rely on spatially distributed tuples for both representing contextual information and supporting uncoupled and adaptive interactions between application components. The middleware propagates tuples across a network on the basis of application-specific patterns and adaptively re-shapes the resulting distributed structures accordingly to changes in the network topology. Application components can locally "sense" these structures and exploit them to acquire contextual information and carry on complex coordination activities in an adaptive way. Several examples show the effectiveness of the TOTA approach.