Reddit mentions of Top 115 Unusual Things to See in Ontario

I like to go to the Kingston area. Get off the 401 at Belleville and take 62 to 33 (Loyalist Parkway). Go past Lake on the Mountain and take the Glenora ferry and continue along 33 into Kingston. Have ice cream at White Mountain and have a beer at the Kingston Brew Pub.

Of course there's always Niagara Falls. I usually go in the winter when the crowds are low and the Festival of Lights is on. Grab a cheap ticket from Costco for the Fallsview Indoor Waterpark. Had an awesome afternoon tea at the Queen Charlotte Tea Room, but if that's not your cup of tea they have lots of other British comfort foods too. Jamie Kennedy has a restaurant in Niagara called Windows if that's more your style. Mostly a lot of bad chain restaurants otherwise. And of course the casino, if that's your thing.

If you haven't seen them before, it's worth the drive to see the Cheltenham Badlands.

Go on a tour of Lake Muskoka on a steamship out of Gravenhurst.

Do you have any particular interests? If you like planes, try the Canadian Warplane Heritage Museum near Hamilton, home of one of only two functional Lancaster bombers.

This is really too far to do as a day trip, but I've also been to the Diefenbunker near Ottawa and that was pretty neat.

Try some of these suggestions too:

• Wheels - Top 10 One-Day Road Trips from Toronto
  
  
• 10 Reasons to Ditch Toronto for a Day
  
  If you have time, swing by the Ontario Tourism travel centre at the south part (street level) of Atrium on Bay. They have loads of brochures that will give you more ideas. And usually coupons too.
  
  My parents have a copy of Top 115 Unusual Things to See in Ontario and it had some neat suggestions. The library has 97 copies.
  
  Edit to add: I could probably come up with a dozen more if you want more...