We had the Slush Festival here in Ithaca back in the '80s. We had one in '83 I believe it was and in '84 we had the 5th Annual. Skipped a couple of years and had another '87 if I remember. That was the 101st Annual.

Quick google shows that Rochester, NY explicitly denies ever having had a Slush Festival (http://www.rnychamber.com/relocating/residents.shtml).

Toadsuck, NE claims to have one (http://www.capnwacky.com/forum/messages/521.html) but there is some question whether Toadsuck, NE even exists.