In this poster we summarize our innovative approach called opportunistic composition: using a bottom-up approach, composite services are built, from available basic services and human-machine interaction fragments, to be presented to the user. In such a way, services emerge from the environment. Our contribution is twofold. The first aims to develop a context-aware distributed engine able to make adequate decisions at runtime about service composition, build and activate adapted composite services and their user-interface. The second contribution consists of presenting on the fly an emergent service to the user and let her or him modify and/or validate it.