Linux: If you’re looking to easily time the tasks you do on and around your computer (like how much time you spend coding, goofing around on time wasting sites, etc.), Light Tasks makes the process dead simple.
How dead simple? Install it, run it, press the “Add new task” button, label the task, and then simply click the color-coded button to start and stop time tracking for that task. According to the developer’s page a Windows version is on the way. Hit up the link below to grab a copy for Linux.