"Grody to the max" is a term in Valley Speak or valspeak from the 1980's. In 1982 Frank Zappa had a hit song entitled "Valley Girl" in which his daughter Moon Unit Zappa laid down some Valley Girl phrases like "Gag me with a spoon".
According to online resources, Valspeak or Valley Speak originated in Southern California in the 70's but was popularized in the 80's.
I hope the little container doesn't barf you out too much.
Update; the container used to be a fake piece of bubble bum magnetized to the sign. It is too weak to withstand storm winds and has been replaced with a sturdier larger container.