categories for appointments and tasks
in most calendars it's possible to add appointments and tasks to a category, that can be choosed in the edit view or in the menu. it will be great to set a color for a category.
I am not sure if I understand you correctly, but I think that’s already implemented. Categories are called “Calendars” in Google Calendar. Just create one calendar for each of your categories and save your appointments into it. You can select the calendar/category in the edit view. Please see here: http://android.calengoo.com/pagedoc/pageinstallation/pagecalendars/pagecalendars.html
And for tasks you can do the same with task lists. Please see here: http://android.calengoo.com/pagedoc/pageinstallation/pagetasks/pagetasks.html
And you can set a color for each calendar/category and task list.
Please tell me ( android@calengoo.com ) if you have any problems or questions.