The oldest ballet company in the country will be looking very fresh this Sunday at 2, performing in the sylvan splendor of Stern Grove. The SF Ballet will be dancing selections from the current repertory. The Ballet Orchestra will be live. There’s a pre-concert art talk at noon in the Trocadero Clubhouse. Everyone who goes to these concerts knows to arrive very, very early with a blanket, a picnic and spare sweaters. Free.