My friend and I took a nice hike up to the lookout in Parc du Mont Royal. It was a bit confusing because we didn't exactly know where we were going, but we asked for directions and figured it out. If you start from the main entrance on the east side of the park, you walk up to the main road, take a left onto the road, and follow it up. There were a lot of shortcuts over the switchbacks but I didn't really want to get lost, so I didn't take any of them.
As people have mentioned, the main entrance was filled with drummers (?). Everyone tries to be hip in Montreal. The lookout area was nice and there's a building up there and some plaques pointing out the various sights of Montreal. There's also higher ground at the real summit, but we didn't have time to go there.
On our way back to the main entrance, we encountered a bunch of people dressed in medieval gear, battling each other. It was pretty cool. They divided up into two groups. Someone signaled the beginning of the battle and they charged each other with padded swords and shields. Typical rules: if you're hit on the arm or leg, it's disabled. Everyone keeps fighting until one army is completely disabled. There were some archers, too, but foam tipped arrows didn't seem very effective as they didn't fly far or straight. I thought it was funny how the 10 year old kids hung at the back of the army and tried to rush in for a few quick flurries.