We envision a future in which clouds of microcomputers can be sprayed in an environment to provide, by spontaneously networking with each other, an endlessly range of futuristic applications. However, beside the vision, spraying may also act as a powerful metaphor for a range of other scenarios that are already under formation, from ad hoc networks of embedded and mobile devices to worldwide distributed computing. After having detailed the different spray computers scenarios and their applications, this paper discusses the issues related to the design and development of spray computer applications, issues which call for novel autonomic approaches exploiting self-organization as first-class tools. Finally, this paper presents the key research efforts being taken in the area and attempts at defining a rough research agenda.