Every area of Japan is "famous" for something, and the Japanese pride themselves in knowing what every area is known for. Perhaps it's how geography is taught.
Kamakura is known for the Daibutsu, the beach and purple sweet potatoes, but this ice cream is perhaps my favorite thing that comes from there. It's a twist of purple sweet potato (beni-imo) and matcha, and is called Hydrangea-flavored ice cream. Of course, Kamakura is also known for the hydrangeas that bloom in the spring.