Windows only: Free, open source application Personal Task Manager (PTM) tracks how you spend your time at the computer. The application is developed to look and feel a bit like the Windows Task Manager, but it's goal is to help you manage a completely different breed of tasks. As soon as you run PTM, it starts tracking what applications you're using and when you're not using your computer and logs all of that data to your database. Once it's been running for a bit, take a look at the mile-high stats and charts to get a better idea of how and where you're spending your computing time. PTM is basically an open source version of previously mentioned trackers like Slife and RescueTime, so if those looked useful to you, this one might be worth a glance. Thanks Manuel!