This paper presents GRiNGA, a middleware based on service-oriented grids to support the development of interactive TV applications. The nodes of GRiNGA are typically personal devices of a Home Area Network (HAN), such as notebooks and mobile phones, which can be accessed by a settop box with Ginga middleware, the standard component of the Brazilian Digital Television System (SBTVD). GRiNGA (Grid + Ginga) takes advantages of idle resources from HAN devices, in order to improve the execution of more demanding interactive applications.