My sons have loved getting their letters. My eldest took the first one they got, along with the map, into school (Year 1) and it has been read by all the children and the map was put up on the wall and poured over by the entire class daily. My middle one was searching the house today for the next letter and keeps asking why the elves only come at night. They are getting their next one in the morning, along with some chocolate coins in the little elf sacks.
International Elf Service
Making Reading FUN! ... Personalised Mail from the Most Magical Post Office