It’s another big weekend at the Maine Savings Amphitheater, with Foreigner, Styx and REO Speedwagon on Saturday and the Smashing Pumpkins on Sunday. It’s also weekend two of the Bangor State Fair, which closes out on Saturday evening, and the Maine Lobster Festival continues through Sunday in Rockland. At 7 p.m. Saturday, Penobscot Theatre Co. hosts its “50 Years of Musical Theatre” concert experience, featuring songs from beloved PTC productions past. Saturday also brings the Bluegrass and Blueberries Festival at the Winterport Union Meeting House, set for noon to 4 p.m.