My Xbox 360 has started writing its own blog. It only has one post as of this writing, but more will follow. My 360 refers to me by my Xbox Live gamertag, "RGBA."
Read my Xbox 360's blog here.
The 360 keeps track of a lot of information. As long as you don't keep it private, this data is used to generate all sorts of crazy things...my gamercard on the top right of this page, gaming statistics, rankings, and, apparently, a blog! This blog is computer-generated using actual information about how I've used my Xbox 360.
To have your Xbox 360 start its own blog, register here. It takes about two days for the first post to show up.