Derek Dukes was on net@nite #53 the other week, and it was really interesting to hear him talk about dipity.
Dipity is an experiment in information organisation, with time being the primary dimension currently being explored. Similar in a way to MIT's SMILE widget, which I was investigating a while back for visualizing time-based information.
Dipity shows a great deal of promise, and I like its emphasis on self-discovery and organisation information if directed (rather than everything having to be painstakingly entered). It is certainly a fun way to get lost for a few hours and learn a whole lot of stuff you never set out to study (just go to the home page and start checking out different timelines!)
Ulrich has already worked up a history of Oracle Releases. Not complete, but a fantastic visualisation that would be worth supporting and maintaining!
NB: I'm posting a static image here for now, because the embed code doesn't seem to work in all browsers at the moment.