Both of my kids love Legos, and they ask for them at just about every gift-giving occasion. It's also a way to celebrate certain moments, such as when Sam got his junior black belt, described here. Sam is rather amazing in his construction abilities. He loves the complex sets and following the elaborate instructions.
Anya is good at that too. But this girl especially loves what I find magical about Legos: free-form play. She asked for a bunch of random bricks for a couple of gift-giving occasions, and recently she's been using them to build a village. Seven houses, several people. Everyone's got a story. There's the man reading the morning paper, the young people who can only afford "mini-college" and who are rooming together to save money. There's also the alien who is guarding the mayor, and Hedwig the owl (from Harry Potter, of course) looking over the town. There is gold for the townspeople to share, and flowers to make the town prettier. Oh, and what an entertainer in a Wonder Woman outfit and Batman mask!
It amazes me how building and imagination come together to create a whole world like this.