As an avid beer drinker and visiting Toronto, I had to make my way down to Mill St. in the distillery district. Mill St. is the largest restaurant/bar in this area and they have lots of beer and food to make everyone in your group happy.
I came to sample beers and they offer 4 8oz samples in their flight for like $12. Thats 32oz of your choice of craft beer for just $12. They also offer a 4 6oz for cheaper (I think 8). The beer selection is, as you would expect, great. They have their core beers, like the Tank House and Organic as well as a handful of season beers to try.
Beer enthusiasts should plan on bringing DD as you can spend a lot of time trying all the different beers. Depending on the weekend, they open up the brewery to an informal 'open house' of sorts where you can ask questions about the beer making process or learn more about Mill St Brewery.
Also note that this side of the Mill St. gets packed in the afternoons on the weekends. Head over to Mill St. beer hall for more space.