Thursday is the first day of summer also known as the summer solstice.That ushers in all sorts of fun things going on including fireworks, free milkshakes, GM River Days in downtown Detroit and the Macomb County Bicentennial Torch Relay.Have a blastMunicipal fireworks shows are set for tonight, weather permitting, in New Baltimore and Friday in Mount Clemens (more on that one below) and St.