What Happens At Grandma's House Kids T-Shirt. Brand New. This is A Unisex Children's T-Shirt. Each shirt is screen printed with the phrase, "What Happens At Grandma's House Stays At Grandma's House" Exclusively yours from Gone Blue.com. Great for gifts for your child's everyday use. This Print comes in a variety of colors to be worn by both young boys or girls. Get your child one today. 100 percent cotton.