Project Folk Fest
Since 2000 I've served as the Database admin for the Camping Committee of the Philadelphia Folk Festival. That involves generating mailing lists and collecting registrations for about 800 active volunteers at any given time.
In 2001 I wrote a web interface to the database, and I've been maintaining it ever since. The committee loves it. Registrations have improved. This year I'll be adding community building features along the lines of facebook or MySpace.
That website is normally at http://camping.etoyoc.com, but it's only maintained for the registration season.