People that live in Amsterdam don't do this almost ever. Nope. But you bet that every single one has done it at least once in his life. Waterfietsen (water biking) is great if you are a kid, but maybe even more fun when you are a grown up.
Just like doing a canal cruise, waterfietsen shows you the city from a different side. And besides, now you finally don't have to constantly watch out for regular bikers rushing by..
Waterfietsen is possible at several places in Amsterdam, but the views in the west part (near the Westerkerk and Anne Frank House) are the best.