Both of the Birthdays I have spent in Korea have been highlighted by amazingly sweet cards from my students.
My most prized 'thing' I took away from the year I spent at Daegyo Elementary was my Birthday card from the girls in 6-3 class. They wrote me little notes and drew me a great picture and even laminated it for me. It has since been hung up in both the places I lived last year, and is waiting at my Mom's house for when I come back.
Korean kids give the best Birthday Cards. It has happened enough that I will claim it as fact.