We are experimenting with a new event calendar and would like your feedback. It's nationwide, uses a scrolling map to determine search area, and lets you pick one or more tags ("Road Race", "Clinic", "Fondo", etc) to filter by. You can bookmark events to receive email reminders ahead of important dates like registration open, close, and of course the event date itself.
Here is the URL: https://www.voo.st/events 
We have imported the USAC calendar for 2012 and are working to get additional events included. Of course, event organizers can add events or take over the automagically generated pages - we try to provide interesting metrics about who is visiting and bookmarking your event. We're also working on giving organizers a way to contact bookmarkers with announcements.
All this is separate from the registration system that Voost offers - it doesn't matter if you use bikereg or usac or any other online registration system (or none at all), you can still add events to the calendar.
We would love feedback about this - is it useful? Are there other search features you would like to see? Do you have any problems viewing it with ?
Jon & Jeff