(Poster art by Dennis McGregor) The 25th annual Sisters Folk Festival (SFF) is less than 100 days away! As of this morning, a limited number of single-day festival tickets are available for purchase: Friday, September 30 – $85/person ($40 youth 17 and under) Saturday, October 1 – $125/person ($60 youth 17 and under) Sunday, October 2 – $75/person…