Hahah, now that would be a bit too much
The notepad example is very good. It depends a bit what kind of application your making. If your making something like that notepad that has a database with an object: the note as its base. You make one activity to edit it, one to view it, one to view a list of all the notes. They even got a separate activity for editting the title (a bit too much i think, maybe just to demonstrate some intent functionality).
Another example.. A IM client. You could have main activity where you can login (starts a popup), change settings. One activity as a list of all your little friends who are online, an activity as a conversation.
A good way is to think and use intents alot. Let one activity catch just a few intents. In the IM, a intent could be: start_conversation. So you need an activity for that, or send_file, or idk.. So that, another application could say: start_conversation, you could handle it, and let the user talk to the person. (Bad example maybe)
Note that, an activity still has a menu, usually, when you click a menu option, either, some little changes are made, or it fires a new intent, or shows a popup, to make some changes then.