Tiny Time Tracker is an unobtrusive personal time tracker that fits nicely at the bottom of your screen. Switching between tasks is made easy with auto-complete and a "task history" dropdown. Times may be viewed in an OpenOffice or Excel spreadsheet.
Simply type in what you're doing in the taskbar 'tracker box', press Enter, and it will begin recording your time.
You can also create a chart in your timecard to show how your time was spent for the week.
OS Independent (Written in an interpreted language). Java required.
Hosted at SourceForge: Tiny Time Tracker