A few years ago, maybe 5 or so, I rented some jet skis at "Sports Rent" in Arvada. At that time they had a 12 or 14 foot boat with a 15 horse merc tiller steer on it. I have no idea how much it was to rent. I looked up "Sports Rent" in the phone book-303-467-0200. You can also rent boats at a lot of lakes that have a decent Marina, but only to use on that lake.