We've just launched a new site at chron8.com that allows you and others to enter any number of events with dates, then shows these events as a graphical timeline. You can superimpose several timelines on top of each other, to see how they relate. A previous blog post explains how this helped me to find some patterns in musical composition dates.
You can make a timeline private, so only you and people you invite can see it, or you can make it public, so anyone can see it.
To view a timeline, just click on the checkbox. Uncheck the box to remove it from view again.
Please try it out, and leave a comment to let us know what you think.