“Hamster is extremely simple without being too dumbed-down. With
a simple menu bar applet, you can bring up a new activity. Just
type in the activity’s name, tags, click the Start button, and go
back to work. When you start a new activity, it’ll stop the current
one, or you can stop it manually. The overview is very nice, and
you can view it in many different layouts, which is great.
Hamster also has the advantage of being the only popular Time
Tracker on Linux that works mostly out of the box.