I've been to the Biodome countless times since I was a kid and it's always a fun time. I've been to Montreal twice this year and both times I've visited the Biodome. In the summer, I was disappointed to learn that the arctic/antarctic exhibit was closed, which meant no penguins for me.
But when I went back last weekend with a few people that had never been, the penguins were back!
So essentially, it's an indoor zoo. But unlike regular zoos, the animals aren't caged in. You actually walk through and experience their environment. The first room is the tropical jungle so naturally it's hot in steamy (there's a coat check downstairs if you don't want to carry it around as you won't be needing it!). As you walk through keep your eyes open and TAKE YOUR TIME! There are so many animals just resting high up in the trees and if you don't look for them, you'll miss out.
After the jungle comes the typical north american forest then the St. Lawrence seaway marine environment and finally the PENGUINS!
It costs $16 for adults, unless you go with someone who is a resident or speaks French and can pretend to be a resident, then it's $2 off!
It takes an hour or two to get through it and it's definitely worth it!