Incorporating a blog into an existing website

[escargot]

Is there some kind of pre-built php script I can simply put onto a page that will then display the contents of a blog?

For example, twitter has this doodaa that you can copy & paste into the site code that will display your twitter updates.

I suspect something similar exists for blogging but I don't really fancy going the whole hog with redeveloping the site in wordpress or similar.