I just learned that the Silent Film Society of Chicago's "Silent Summer 2005" festival has been rescheduled for the fall. It will also be at a different venue.
The guy at the SFSC was very nice and polite about it, but it sounds like they had a lot of challenges trying to make it happen this summer. He assured me that next year they'll be back on during the usual months.
In the meantime, keep an eye on their site for the festival announcement.