Back in the mid-sixties, police officers came to our school and showed us a movie on bicycle safety. It was hilarious - I remember there were monkeys riding bikes, crashing into things and falling down manholes. We laughed so hard. I'd recently been thinking I should see if I could find it online. But then I read in the Cascade Courier (the paper of the Cascade Bicycle Club), that a movie called One Got Fat was going to be shown at the Bicycle Film Shorts Festival at the Seattle REI:
"A group of children, all wearing ape masks, ride their bicycles to the park for a picnic. Along the way, all but one are eliminated for violating basic bike safety rules...A true bicycle comedy classic." It had to be the same movie, if a little different than I remembered.
Here's a link to it at the Moving Image Archive: One Got Fat.
Still funny if a little macabre. It's 15 minutes long and includes some cool bikes. I saw a little of myself in a few of the poor little bikers.
We were shown a different movie at school the following year, I'm not sure why.