This actually hasn't happened in my childhood, but when I worked at McDonald's I had convinced every person, from the owner of the restaurant, to the lowly employees that I was the thumb wrestling champion from 1993 to 1997. To prove it, I beat everyone who worked there in gentlemanly combat, save for an old military vet. I left him alone.
As for childhood memories, I did a lot of things. I can't really put my finger on any one thing. I've always been a good liar, but I didn't learn to control that until I got older. Suffice it to say, I had convinced people that I knew how to make my own envelopes in kindergarten, I was the owner of the school in first or second grade, I had my own cross bred tiger/wolf in about third grade, I had super mental powers in fourth grade, and sometime later that same year I convinced them I was a martial arts master when that lie fell through. Those are the things that really stand out. I got caught a lot and my strategy was to usually lie through it and it worked too often than I'd care to admit. Ahh youth..
Now as for siblings? Nothing. I was the youngest and most foolish. I got tricked a lot with sneaky lies, but I had my revenge via pranks.
