The Sag Harbor American Music Festival is now officially an annual event, after the resounding success of the inaugural event last year. Live music will again fill the streets, restaurants, galleries, shops, and historic spots throughout the village beginning on Friday, Sept. 28, and continuing with free shows the next day. The number and variety of musicians and venues have taken a huge jump, with more than 20 musical acts scheduled to perform outside, all with contingency plans should rain overcome shine.