Mark your calendar for Saturday. April 9^th, when the Friends of Mendon Elders will hold their Third Annual Book Fair at the Senior Center, 62 Providence Road, Mendon.  This popular event, which will be their biggest yet, will begin at 9 AM and continue until 2 PM. The volunteers have been busy sorting books, all unbelievably priced at no more than a dollar each.  In addition to the many books, a large assortment of  Sci-fi books, craft and Harry Potter collections, Puzzles, CDs, DVDs, cassette tapes and previously viewed videos will be available for sale as well. Assorted donations are arriving daily, just waiting to be scooped up by savvy bargain hunters.  Contributions of books and related items are welcome and can be dropped off at the Senior Center weekdays from 8:30 to 3:30 or call 508-478-6175 and leave a message at the Senior Center to make other arrangements.