Wikipedia Diver may be one of the most interesting, albeit niche-based, Web history tracking and organizing tools. This Firefox add-on gives you a visual history of everywhere you've been on Wikipedia, and organizes it down to the day, order, and session in which you visited the sites, making it easy to revisit old entries.
Each visited page is presented as a small red globe that you can click on to advance the timeline. There's also a source list of every site you visited, that will take you right to the page. Like some other Web history trackers, Wikipedia Diver intelligently tracks when you hit the back button on your browser. Each time you leave whatever Wikipedia entry you're on to visit a link that's on that page, it simply attaches it to your history. In one entry we were looking at, we had clicked on seven different links that were on that page, and the extension kept track of how we had arrived at each of those pages. That in itself can be fun to observe.
One thing it does not track are the reference links you click when exiting the site to view a source. While it would make a cool option, it veers uncomfortably into the realm of watching everything you do. Also worth a mention is that all of this data is kept locally, and never sent to the cloud. Wikipedia Diver gives you a fun and interesting way to track your wiki-browsing.