Most people nowadays will use eBay.ca or Kijiji.ca and post an auction of the DVDs that they are willing to part with. It can be done as an auction or a "sell now" price. Keep in mind that it is illegal to sell pirated copies of any copyrighted DVDs, and you can be reported to authorities if the DVDs you are selling are not the originals you bought or received as gifts.
You may be able to find a local second-hand store that buys them. Perhaps Busters located on Queen Street near Highway 410? More likely, a place that sells used records, CDs, and DVDs would be interested.
Most DVDs cost from $20-30 when brand new, and then quickly drop after they are six months to a year old. It is not uncommon to find DVDs on sale for as low as $5 at places like Walmart, Zellers, Futureshop, Best Buy, and Giant Tiger discount stores. So I would not expect to sell them for too high a price.
By the way, if all you want to do is get rid of the DVDs you never watch and it is not for the money, you could try a DVD swap website. I have heard that there are places that allow you to post online. You tell them the DVDs you no longer want, and what you are looking for. Someone offers you a trade. Your copy of "Shrek II" for a copy of "A Knight's Tale", that sort of thing.