SimpleTrack

SimpleTrack provides task tracking functionality with the look, feel and simplicity of sticky notes. As such, it
   – uses only a small amount of screen real estate;
   – allows a new task to be created in seconds;
   – supports typical sticky note colors,
while in addition, it
   – automatically marks the date and time of a new task;
   – allows tasks to be marked as completed with a single click;
   – automatically marks the date and time of task completion;
   – automatically removes completed tasks from the list;
   – allows review of all completed tasks.

Those are the basics. There are several other functions; see User Manual for details.

Screenshot