The Halton Hilly Hundred is a 100K route through Niagara escarpment country. It's a beautiful area just west of the GTA that gives a pretty wicked challenge for any cyclist.
Over the course of the ride, you climb the escarpment 5 times... they are long and steep climbs by Ontario standards, making this route a very tough metric century!
The route is documented here, including a route map.
Not doing anything May 18th? Join us to take on this beast! Details are here. Nothing formal, just a couple of us hitting the route together. Please note the speed we intend to ride, and make sure your abilities match (although no matter who you are, you're going to climb those hills faster than my 190+ pound butt!!!).
There is also a charity ride for MS that will do this route later this summer.
Enjoy! And suffffer... :)