Have you seen the latest cool WordPress toy?
?random to the end of your WordPress.com URL it will redirect you to a random post on your blog. You can then use it as a link in a sidebar text widget as I’ve done, or else just go to the admin bar when you’re logged in and when you hover over “blog info” the first menu item is a random post link.
It’s quite fun visiting random posts on other people’s blogs, especially on those that I’ve only come across recently. 😎