Saw some people white water rafting on the Arve between Chamonix and Les Bossons today when coming into work. Looked like quite a giggle and was thinking about getting a few people together to give it a crack. The trouble is that it's glacial water - you'd end up with testicles the size and texture of raisins after 5 minutes in that river. It's bloody cold. Still, looks like an entertaining way to spend an afternoon.
One of the cool things is that you get to go through Chamonix town centre itself.
Boshing through Cham past Le Terrasse