RaceReplay.net is 'live'... well, in beta form anyway.
Turns out Silverlight is a great medium for .NET developers to get on the RIA bandwagon. Flash always had a big learning curve - probably due to it's "designer-focused" background - but Silverlight and Xaml just seems to 'make sense' (to me, at least).
OT: Russ just pointed me to Flickrleech - waaay cool viewer for flickr photos.
EDIT: Silverlight vs. Flash: The Developer Story is an interesting point-of-view... although it was a loong time ago that I last developed anything in Flash, certainly they Silverlight platform makes a lot more "sense" to me.