Service-oriented architectures are among the premier middleware approaches to coping with the dynamicity of ubiquitous computing environments. In this article, we propose a new way of integrating services, namely ad-hoc service integration. For a certain class of services, ad-hoc integration is capable of automatically combining services at run time. This allows generating new functionalities from services newly appearing or already being available in the Ubicomp environment, but leaving the services' interfaces unchanged. This way, the extension in service functionality can be kept transparent to applications or users of a service. Nevertheless, our service-integration framework can more precisely distinguish among services. To show the feasibility of ad-hoc integration, we have implemented our service-integration framework based on OSGi/Felix along with a toolkit providing two different techniques to realize the ad-hoc integration: Redirection, i.e. calling interfaces and replication, i.e. copying implementations of services. A first evaluation verifies the viability of our work.