The other day, I was playing "Niagara" with my wife and daughter. My daughter had played once, and my never, so I was teaching them. While explaining the rules, I included one rule that I learned from another player when I first played the game: there can be no more than two canoes on a river space, and a space with two canoes blocks further travel up or down the river.

My daughter used this rule to block both my wife and I down river, then forced us both over the falls with the cloud. She ended up winning, and I was pleased to see she had used this rule to play the game we always told her to play "Puerto Rico:" "screw your neighbor."