I recently added the Out of Milk app to my phone and it's great! I thought an imbedded app of a similar nature in Kona - especially mobile - would be great. It not only allows you to create a shopping or to do list, but after you add, for example, butter, and buy butter, you can remove it from the list or just cross it off until you need it again. It's not just simple list creation, but a catalog of items that ebbs and flows in the user's control.
Shopping/To Do List