If you happen to be in the area of Hannibal, Missouri, or if you're up for a trip, you might want to look up the Mark Twain Boyhood Home and Museum, which will be offering adult writers' workshops, according to the Hannibal Courier-Post.
The workshops will take place throughout the fall, and will be run by Dr. Cindy Lovell, the museum's executive director. Naturally, a large part of the contents of the workshop will be drawn from Mark Twain's own advice to writers. As writing advice goes, I can't imagine it gets much more reliable than that!
“We’ll begin with these one-day workshops and see if there is an interest in expanding them into something like a writers’ weekend at some point,” Lovell said. “For now it will be fun to use Mark Twain’s writing advice as a jumping off point for writers. It will be fun.”
For more information on the where, when and how, check out the official website of the Mark Twain Museum.