I have loved this idea for years. I had wanted this same app when the iphone first came out.
However, it would be great if some of these activities can be triggered based on GPS location rather than clicking.
What about setting waypoints to track between. I set a waypoing GPS location for my home. Then I set one at the rain station near my house, then again near my job and finally at my job.
Measure commute times between all these points automatically.