The simplest way to describe what I am trying to do is a ToDo List...

I want a list of things to do (with a submission form to add to the list), then a view of the tasks. Here is the catch, as I do the things on the things on the list, I want (I think some sort of validation formula) to display a checkmark.gif file either before or after the item on the list if it is something I have marked as completed.

The concept seems simple enough, is it really?