Which fantasy MMORPG by Blizzard Entertainment was originally released in 2004?

World of Warcraft

Which Christmas hymn's Latin title is 'Adeste Fideles'? Which country celebrates 'Little Christmas' on January 6th as the traditional end to the holiday season? Which landmark is featured on Cambodia's national flag? What is the name of the multi-colored tune-playing instrument in Ocarina of Time? What do you call a triangle with three unequal sides?