Is there such a thing as a Diary app?

It's a simple thing to start at the top of a Word document and type ... Jan 1st 2011 and write whatever you need to followed by Jan 2nd 2011 etc, etc, etc but is there a piece of software already out there that lets you just fill in the blanks?
Cheers,
Steve

If you open the Mac App store and type "diary" in the search bar, it pulls up 10 of them...

I like MacJournal. It's a decent journaling app with hooks into most social media sites if you want to publish something, or if you want to keep it completely private, locks and encrypts with AES-256 bit encryption. I used to use this app to store all my server administrator passwords.