There are several companies which provide great Hell's Canyon rafting, jetboat and kayaking adventures.  The length of the trips vary, as do prices and types.

www.hellscanyonraft.com

http://www.rowadventures.com/hells-ca...

http://www.hellscanyonadventures.com/

http://www.hellscanyonadventures.com/

http://www.hughesriver.com/snake-river/

http://www.windingwatersrafting.com/r...

http://rafting.allaboutrivers.com/Ida...

http://northstar-rafting.com/