Friday & Saturday, April 26 & 27:  Big Island Chocolate Festival.  The chocolate extravaganza includes a cacao plantation tour at Original Hawaiian Chocolate Factory, a college culinary competition and several public foodie and agriculture-themed seminars. Activities culminate 5 to 9 p.m. on Saturday, with the indoor-outdoor festival gala.  Enjoy a host of sweet and savory culinary stations presented by top isle chefs, chocolatiers and confectioners. Fun chocolate activities include chocolate body painting. There will be food booths, unlimited wine and…