Austin City Limits is the last weekend of September. Always a good time. Three day passes are sold out, but you can scalp some either off Craigslist or outside the gates. http://aclfest.com/default.aspx
NY harvest festival & freedom festival. October 10-13 music and arts festival + marijuana awareness festival http://www.damnsam.com/index.html
terrapin hill harvest fest. Its in central kentucky. looks to be a damn good time http://www.terrapinhillfarm.com/festival/