A derogatory term but some people aspire to be them after seeing many cheesy old 60's films. It is used to describe people who have giant grins and a extrememly happy/weird face no matter the occasion.
They resemble Ron Howard, commonly known for his role on happy days.
Rich: Look at that man in that van
James: What a Goonie Face
Lee: Why don't we become hippys and enjoy life like lennon would
Peter: No, cus were not a Goonie-Face
Dad: Son, If you keep smiling like that You will become a Goonie Face
Son: Okie dokie, ill eat a lemon for the sourness and not smile