I've recently started 'Going out of the the building for business' and have to wait at a lot of places, and I have this urge to know How long it's been since I started waiting for some one, or how long It took me to finish something. One the desktop I use the awesome gtimelog. However, I had no way to do the same when I was not using my computer. Until I noticed that my phone had a call register with timestamps. All I had to do, to log my time on an ordinary phone was call my own number, to store the call timestamps whenever I started something. Now, I know how much time I spend on different things and I can optimize it. Hope you find it helpful.