Prompt for recent activity at configurable intervals.

A dialogue is to be regularly displayed, prompting "What have you been up to for the last {x} minutes?" (or similar). The goal is to have users book tasks to activities.

1) This dialogue should allow the allocation of a new or predefined task (or multiple tasks) to a new or predefined activity (or activities).
2) If multiple activities have been undertaken since the last prompt, then the time period may be split (for efforts in series) or shared (for parallel efforts) across these activities.
3) Different 'people involved' can be assigned to each activity record.