SimpleToDo is a very minimalistic to-do application developed by Julius Eckert. The only functions are to add a task, and to remove finished tasks. To add to the minimalist approach, everything in SimpleToDo can be manipulated with a keyboard if you're that type of person. Julius even offers a Quicksilver plugin for SimpleToDo so you can easily add a to-do via Quicksilver. If you just haven't found that perfect to-do manager, SimpleToDo is definitely one to check out.