The web should be a place where you can wander off to unexpected places. However that's not what my browser gives me. Everything about the browser pulls me back into the part of the web that I'm already familiar: the history pane, the bookmarks menu, the address bar combo box all do this.
Even blog aggregators, Google and del.icio.us give me sites based on my own input. They are more dynamic and provides more variety. But after a while, I find myself reading the same set of bloggers, subscribed to the same set of tags, and searching for the same set of topics.
Then, a few days ago, I stumbled upon a blog entry, I forgot who's, that mentioned StumbleUpon. It's one of those "we'll give you some fresh sites" kind of deal. It gives you a web toolbar with a "Stumble" button. One click and you are on a totally unfamiliar page. There are also "I like it!" and "No more like this" buttons.
I haven't tried doing anything fancy yet. I just selected my interest areas (away from the usual computer stuff) and started to stumble.
So far, the sites suggested have all been refreshing, unfamiliar, surprising, and of high quality.