Okay guys, here's a story from last night.
I was walking down the street at around ten o'clock at night. A tourist and his wife were walking down the street a little ways in front of me. Two egyptian boys (probably in their early teens) were riding their bike down the street coming towards me. As they passed the couple, one of the boys reached out and tried to touch the girl. She jumped and screamed.
So as the boys rode past me, I pushed their bike over. They looked up at me with a surprised expression, and I started lecturing them. "What? You don't like it when someone gets in your way? It's not okay if someone touches you when you're going down the street?" I was about as sarcastic and mocking as I can manage in Arabic. After I finished, they rode off on their bike. I heard them laughing as they rode away.
It was a nice moment of poetic justice :)