The need to involve business users in process modeling is largely perceived in the context of Business Process Management systems. This can facilitate the elaboration of consistent process models which are better turned to users' needs and organizational changes. Despite the variety of tools and notations, process modeling remains hardly accessible for business users, who lack advanced technical skills. This paper presents an integrated approach for end-user driven business process modeling which uses web service based activity tracking to generate weakly-structured process models by capturing data on personal task management. These models can be adapted and reused for ad-hoc process support or exported to formal workflows by delivering the business knowledge to process designers and software developers. Interconnection of ad-hoc and formal workflows results in enhanced process flexibility and allows complementation of formal workflows through deviations at runtime. The approach i...