The Downtown Rocks Free Concert Series is your main source of headliners that make you go, “Oh hey! Those guys!” Sometimes they’re welcome blasts from the past, like Taking Back Sunday. or All-American Rejects. Other times … maybe they should have stayed back there (looking at you, Rick Springfield). You know Gin Blossoms from their radio hit, “Hey Jealousy,” but they also have a rich catalog of power pop tunes with bright melodies and profound lyrics. Check ’em out, along with the rest of the Downtown Rocks calendar. If the show’s a bust, it’s not like you’re starved for entertainment options in the immediate area.