Thanks to Andrea, last Saturday I tried rafting on Eisack river near Sterzing/Vipiteno. It appeared to be a very nice way to spend half a day and 50 euros. We went down 17 km on two rafts with instructors.

It was not dangerous at all, because we had all the equipment and the instructors were telling us what to do. Besides jumping from the rapids an interesting part was "swimming", when we had to walk into the river until it catches us and then we had to swim out of it to the coast.