Thanks to a conversation with Jon Pincus, I just found out that Page activity (beyond becoming a fan) will hit the facebook newsfeed for the following actions: commenting on video, posting to discussion board, posting to wall, posting a fan video.
What doesn't hit feed: inserting a posted item.
The big aha: if you are the admin of a page, your own activity on the page will not hit your feed. I had to de-admin myself to get this activity to show. Have a friend be your page admin