The August I-LYA regatta.      Hosted by Put In Bay Yatch Club this is a first class event all the way with professional race comittees and party hosts.    The last two years we have stayed on and launched from Middle Bass Island and commuted over daily to the afternoon festivities at Put In Bay.   This is a really great venue and about as nautical as you can get.  Watch for more details come Summer 2008 at  http://www.i-lya.com/
Update:   This is Prodigy One Design Sailing 
Update:   2008 dates are Mon Aug 2 through Wed Aug 4,   registration, checkin, Sunday Aug 1, usually skippers meeting Sunday evening for centerboard boats (windsurfers).