Xtimeline allows you to explore all sorts of user-created timelines from the US war in Iraq to the life of Angelina Jolie to the history of pornography. I think the site is still pretty new since the most viewed timelines for the month, past 3 months, and year are still all the same, but nevertheless, from the looks of things, a nice community seems to be developing over there.
One suggestion -- it looks like timelines can only be ended by a single user. It would be cool if multiple users could contribute to a single timeline, because I think it's hard to remember all the dates (especially the months) for certain events. We can't all be like Victor, who seems to know an awful lot about Britney Spears.
*UPDATE* I just read the xtimeline blog. Yup, xtimeline did in fact, just open up to the public July 1.