For the extreme rich there is the International Space Station as an odd destination. If you are not so fortunate could you spent some time as a tourist on an oil-platform?
Don't think you could visit a live-platform because of safety and insurance regulations - it's pretty much like asking for a tour in a factory or plant, and you would have to go through a safety briefing.
If you wanted to visit an actual working platform, why not get paid for it?
Dishwasher Pete from This American Life did it for two weeks washing dishes. You could, too!