Does anyone know of any basic GTD tool (calendar, todo-list WITH CATEGORIES, etc.) that can run off of a USB flash drive without messing with the system's registry, hard drive etc?
For example, Palm Desktop is inappropriate because it makes extensive changes to the hard drive and the registry. Mozilla Sunbird, while it can run off of a USB drive (see http://johnhaller.com/jh/mozilla/portable_sunbird/ ), unfortunately does not have categorized todos.
Anyone have any ideas?