Best Physics lesson ever
The second less conventional, and less legal on multiple levels part was using my mates Fiat 500 down the road at the front of the school.
The first run was hilarious, my mate drove down the road at 45mph (30 limit ), while I stick my head out of the window playing the harmonica (Well, one continuous note). We later did it again, this time with the car horn instead of the harmonica.
The investigation was half successful, the bike got a value for the speed of sound of 386m/s, only 40-50ish out. The car was not as successful, the sound recording didn't work that well, and somehow the pitch of the horn went up once the car had passed, when it should have gone down. It sounded right on the recording, there was just too much interference to find a good value for the frequency.
Brilliant lesson though.