I know it's kinda late, but just found info on this yesterday at LBS. The ride is prsented by the Memphis Hightailers Bicycle Club, calle dthe Bluff City Blues 100. The date is Oct. 14th, all proceeds go to benefit Revolutions, a non-profit organization looking to further the sport of cycling in Memphis' underprivilaged communities. Go to:
memphishightailers.com

Also not a benefit ride but just a laid back group event happening in the Hattiesburg, MS area.........the Birthday Challenge. For more info:
longleaftrace.org