River Cities Century Ride -
This is a good one! It draws from many states and is a ton of fun!
http://www.mrcride.com/

Delta County Century Ride -
Beautiful UP country side to pedal through, and one killer hill near the end! You will have to call or email for info as of this point. they are typically a little slow to get info on the website..
http://www.deltami.org/events/event.asp?uid=637

Tour De Dickinson -
Another great ride, and there are some great hills and views of the lake country on this one. As of right now you will have to call or email for more info as they also seem to be slow to update the site. It's a U.P. thing! All the modern conveniences of life, but with a much slower, easy going pace....
http://www.tourdedickinson.com/
It's a UP thing.