Shameless plug for my own tracker, in case anyone is interested: I built https://agh.io/about for productivity/time tracking. The advantage is that it's completely passive, but still can accurately classify time spent away from your computer (e.g. driving), zoning out in a puddle of drool with emacs open, talking to a coworker about a project while leaving your browser on HN. Things that most time trackers fail at.
And if you'd rather run things yourself to avoid giving me your data, it's open source, too: https://github.com/johnswanson/tictag