A computer system establishes an execution environment for executing activities in a continuation based runtime including instantiating an activity scheduler configured to perform the following: scheduling activities for execution in the CBR. The activity scheduler resolves the scheduled activity's arguments and variables prior to invoking the scheduled activity using the activity's unique context. The activity scheduler also determines, based on the activity's unique context, whether the scheduled activity comprises a work item that is to be queued at the top of the execution stack and, based on the determination, queues the work item to the execution stack. The computer system executes the work items of the scheduled activity as queued in the execution stack of the established execution environment in the CBR.