I lived in Manitou for nearly a decade (until last year) and always went to the toss. I'd get the archives from the local weekly paper and talk to a guy named Jack Elder, who mostly runs the paper. I don't have an address but he should be easy to find. You could also call the mayor, Marcy Morrison. She's about 70, a shrewd old bird if there ever was one, and would likely recommend someone to talk to.
The best story I ever heard was that we'll never know the distance record for the maximum toss with an assisted device (one of the many categories of competition). People use catapults and all sorts of things. One guy tied a cake to an old weather balloon and let the thing go. It drifted off to west over the nearest mountain, back into Pike national forest, and no one ever found it. I believe it still stands as the record.
Two years ago they had to stop doing it in one of the parks and move to the high school field because people were getting so good the cakes were raining down on the park's neighbors.
Hope this helps. It's a cute little town. They also have a coffin race on Halloween you might look into (The Emma Crawford Race, named for a coffin that reportedly washed into town off a mountain during a heavy rain storm.)
Lived on Spencer Ave, off Canon...