At Tremblant, they have a 'luge' run down the ski hill in the summer, gondola rides to the summit, mini golf, and all other resort amenities a few steps away from the transition area.
The former REV3/Challenge race at Cedar Point had free entry into the park which was pretty cool.
We're hosting a sprint and olympic in Rockford, IL this coming August and the swim is at a wakeboard park with a pretty sweet towline. They are opening it up for free to athletes and families after the swim. Kind of a neat non-triathlon perk.