Starting with a new hourly-paid freelancing job, I needed some software to track the amount of time I spend working. I tried a few time tracking programs out there, but they all turned out to be bloated and clumsy (not to mention not open-source), so I decided to roll my own.
No fancy interface, no useless options. Click the icon to start/stop work. Icon files are purposefully not embedded for ease of customization. Work periods are logged to a text file with a very simple format. You can set the active task using the right-click menu, or a command-line utility. The executables are incredibly tiny, just a few kilobytes (except the report generator, which is written in D).
It will generate reports which look like this: