The Flatest Century of The East is a great century. It's gone on for decades and is well managed and run. I first did it in the 80's on a mtn bike...whew, not easy for awesome.
I rode with the East Prov club on my second run.
It is not a flat century but lots of rollers. In it's heyday you had to sign up early as it sold out quickly. Not sure now but I hope it is as popular.
Good for you...I miss that event.
I still have my patches