Speeding in a school zone

It was a nice morning and fairly cool which was nice for a change. About half way to work I get to ride over a small bridge and then through some light traffic before I am back on the side streets. It was strange as I was riding through the traffic that all the cars seemed to be going so slowly... or was I going fast? I looked behind me and to my left and could see a car not going fast enough to pass me but also not making a turn. I thought it was strange but I changed lanes anyway to prepare to make a left hand turn back on to the side streets. As I changed lanes I looked up and to my right and saw to officers of the law parked on motorcycles watching the traffic go through a school zone. It was at that moment that I realized that I was riding through a school zone and school was now back in session. I also remembered seeing a sign somewhere that made mention of a 20 mph speed limit while in the school zone. A second later I could see one of the officers smile and yell out to me, "Wooooh! 20 mph!!". Smiling, I threw them a cyclist's wave and proceeded to make a left hand turn.