I'll second the Hancock Horizontal Hundred, I like to jokingly call it the Horribly Horiontal Hundred. TOSRV, Hilly Hundred, GOBA of course if you're into a 5ive day event.

A favorite of mine is the Columbus Fall Challenge. 2 days, 16k vertical feet down to Marieta and back.

The Bluegrass 100 in Kentucky is a favorite of many Toledo area riders.

The Oberlin Red Flannel is a favorite fall ride.

I'm going down to the 10th annual Gravel Rouser Classic March 14th. Four days of mixed gravel grinder and singletrack in Athens, OH.

There's a pretty active Randoneering club in Columbus. I believe they do pretty much weekly long distance rides. 66, 100+ miles.