Free app True Time Tracker is extremely simple: Just start it up, let it run in the background, and it will create numerous charts detailing what programs you run, what sites you visit and how much time you spend idle.
We've featured numerous time-tracking applications before, but True Time Tracker offers more simplicity than most. You just start it up and let it run — it will track what programs you use, what websites you visit, and other statistics about how you're spending your time.
If you want to, you can organise your usage by project or subject. Thus, you can use it to categorise your time for the purpose of billing clients (and create invoices straight from the program), or just to see how much time you're wasting (i.e. you can set work websites and programs as "work" and Facebook and Twitter as "time wasters"). If not, though, you can have it print out pie charts of your time management to PDF at any time. If you've found other time-tracking applications a bit too complicated, True Time Tracker is worth a look.
True Time Tracker is a free download, Windows only.