Nobody has mentioned Oregon yet. I live in southern oregon and if you are coming up I-5 you have to stop in Grants Pass Oregon and take a **** Gate Jet boat excursion. They take you on a flat bottom jet boat and you go down the river to a restaurant that is only acessible by river and they feed you a buffet style meal that is to die for. After your meal you continue down river and then back up again. The drivers of the boats are great and give you a guided tour down the river and you go fast and get wet. The trips start around $40 per person to $60 and most include the meal. You get to see the famous Rogue River, where parts of the Meryl Streep film "The River Wild" was filmed. The river is also popular for it rafting trips.
http://www.hellgate.com/Index.asp here is there website, check it out you won't be disappointed. I am a local and I still like to do this every summer.