How old were you when you discovered the truth about Santa Claus!? How did you find out?

I was about 7 or so, and I had peeked at the presents in my mothers room. When one of them showed up in my stocking I was like .

My sister's story is better, she was about 9 and found the receipt for one of her gifts and my mother had to console her in a parking lot as she cried her eyes out.

What about you?