The next time you're in the Niagara Falls area sightseeing or trying your luck at the casino, take a long walk along the Niagara Parks Commission Trail Route along River Road. There's a tourist attraction as part of the Rapids in the Niagara River where you can take a chute down and walk along the about a half mile of a wooden boardwalk, where you'll see the grand rapids up close.
It's exciting to watch and to listen to. The roar of the powerful cyclonic water smashing against rocks can be terrifying, but that's about all you get down there and for the money, I don't really think it's worth it even if it's a one-time deal. Along River Road you'll be able to see some good views as well as stretch your legs after a long drive. 
Here are just a few:
By the way on the way back towards the hyper action of the casino and other Niagara sites, you can check out the Olympic Torch Run Legacy Trail which runs perpendicular to Palmer avenue from Niagara Parkway northeast to Niagara Falls City Hall (it's not very long) only 1and a half kilometres, but it's worth noting.
By the way:
If you are a die-hard tourist though and really need to say you've done it, then you'll walk along to 4330 River Road. The Attraction is called, "White Water Walk"
