You can jetboat the Lachine Rapids or raft them.

One satisfied customer:

As a chattering crowd swarmed the Contemporary Art Museum on the Place-des-Artes and the sidewalk cafes of Old Montreal, in another part of town Don Lindberg, his wife, Sue, and their kids, Brady and Ali, were donning full-body windbreakers and life preservers for a different Montreal experience — a jet boat ride into the Lachine Rapids in the St. Lawrence River.

"They call them Barney suits because they're purple," said Mr. Lindberg. "They don't keep you dry." But probably no suit would, because the jet boat hits a wall of water from 6 to 12 feet tall, as Mr. Lindberg describes it, and the waves "crash over you so that you're completely soaked."

"It was fantastic," he added.

The Lindberg family went through the rapids six times on jet boats run by Les Descentes sur le St.-Laurent on Lasalle Boulevard in southwest Montreal last May. "If we weren't flying home to San Antonio tonight," Mr. Lindberg said, "I'd do it again tomorrow."