This thread seems very useful for the Wakeboarding and Wake Surfing options.
Everyone at my work goes with this bloke in Zurich (and doesn't seem to have been listed before):
http://www.wakeandski.ch/new_page/
The site is all in German, but if you call, they speak English.
There is also Wake Surfing on the above link.
Bungee Surfing :
Also, there has been some banter about the "Bungee Surfing". So here is a link to buy the bungee chord and the gear:
http://www.shakashop.ch/bungee-surfing-c-230_795.html?osCsid=18b621f1ee48d6436df8b81e6ce971 9d
I bought mine online, and I have to say I had two 'very high eyebrows' with how impressed I was with the service at the shaka shop.
They said it would be two days, and it took two days. They follow through with emails to tell you when your order has been confirmed, and when your goods are dispatched.
With Bungee Surfing, the technique is similar to Wakeboarding, but of course the ride is hideously limited....... but with the exception of the set up cost, it's free !!!! (no boat).
The rides however can be repeated once you've got the technique down, so you don't mind so much..... you still get hell tired.
It is true that people died with the Bungee surfing, so make sure you always do this with someone else .
Personally I don't find it dangerous (unless you kook it, and let go of the rope, then everyone on the bridge is at risk).
But take a knife and have someone on the bridge to cut the rope should the unthinkable happen.
Always be aware of others in the river.
River Surfing :
Keep your eyes on this link (set it to your favourites):
http://www.hydrodaten.admin.ch/d/2018.htm
The site is in German but all you need to check is the low in m3.
The flow should be between 220 - 340m3.... over this it gets messy and I assume much more dangerous.(250-300 is ideal)
There was a link posted earlier about an article killing people on this. The guys on the river assured me that this article was abou the Bungee surfers and not the river wave.
Bremgarten packs out, so don't be shocked at the line up.
Happy Swiss Surfing.