I have seen many strange vehicles in the Amsterdam canals but a floating bus I hadn't seen before. This one looks like a normal bus just splashed in the water. I have done this once in the US and found it a rather scary expierence to drive into the water from the road. However that bus was a combination of a bus on a boat and didn't looked like a real bus so much.
This one is different and looks even more scary. I read you can make a tour with this one from the airport Schiphol when you have a long transfer and you don't want to hang around there but want to see the city. So you can drive under the Skinny Bridge with a bus!
See for more Sunday Bridges here
Here you see the testdrive/float.