Course I did. I worked it out pretty quickly though, I think I was 5 or 6. I always stayed up late, and every year I could hear my parents messing about taking all the presents downstairs. But I didn't tell them or confront them about it, I just pretended I still believed in him.
Kind of ironic actually. Looking back, I should have said something and saved them all the hassle of trying to hide everything from me all those years ^^' And now because of my little brother, they're still doing it.
Actually, he finds the idea of a strange man just coming into the house while we're all asleep rather terrifying, but dammit, we ain't spoilin' the magic for 'im!