Bay seniors who have resolved to sharpen their minds in 2015 have a massive number of classes to choose from at various adult and community educational sites, not to mention the plethora of online brain stimulators. What sounds like more fun are the free Adult Italian Classes at Folio Books in Noe Valley. Or more relevantly, Mandarin. Or The Joy of Algebra at the Fromm Institute? Why not harp classes at Harpeggio? Or improve your billiard skills at SF’s Beginner’s Mind Pool School? Or a Donut & Fritters Workshop at the San Francisco Cooking School? Or learn 3-D Printing? Sign up for a bocce ball class? You get my drift.