I had a friend with a sailboat when I was young and though I did go sailing with his family sometimes, I wish I had the chance to ride with them while taking it past the bridges.
Another cool bridge to see is the disused rail bridge at the Northern tip of Goose Island. You can see it easily from North Ave. I passed by quite often as a kid and seeing the giant, concrete counterweight suspended up in the air always made me kind of nervous it would crash down as we were passing by.