Cool river riding (Quicktime) video here: http://www.digave.com/videos_ice.html This was the Charles River in Boston during that real cold snap a couple of years ago. Other "extreme" bike videos at http://www.digave.com/videos/

Somewhere I have an old photo of my parent's 73 Ford station wagon parked at the dock at their place in the Rideau Lakes about halfway between Kingston and Ottawa, Ontario, and pics of ten-wheel dump trucks driving across the lake too. Ice hasn't gotten that thick in a few years though.