I'm sure that there's a lot of things that can be done in 15 minutes. Buying auto insurance, for example. Grilling a burger (not necessarily eating it too, but I'm sure it's possible). Reading about 200 tweets on Twitter, as long as you don't read a lot of linked articles.
Having sex, if you don't count foreplay or keep the preliminaries short.
And another thing that people may be able to do, for about 15 minutes, is be in space, above most of Earth's atmosphere. There are several companies now that plan to make this possible -- here's an article about Blue Origin, a company led by Amazon's Jeff Bezos, that's going to have a space capsule with big windows.
'The largest windows in space': Inside Blue Origin's New Shepard flight capsule that will take tourists to into orbit next year
|You could get married up there... and, well, you know...|
The thing is... there aren't any neighbors up there to LOOK in the windows.
So if some pioneering couple wants to be the first-ever members of the Highest-Ever club, they could pay for an exclusive two-seat ride. And ignore the view.
High price to pay for history? Depends on how much you want to be historical. And hey, you could look out the windows while engaged in the history-making act. People do it in their private beach rooms all the time.