Not too long at all, really.
Ten minutes is just a little more time than it takes to smoke a cigarette. Less time than it takes to drive down to the local fast food joint to pick up a quick dinner. One-third of the time it takes to watch another formulaic, unfunny sitcom, including commercials. One minute more than your average snooze button lasts. Definitely less time than it takes to get the cat in the car for a trip to the vet.
In the grand scheme of your life, ten minutes is nothing.
So, take ten minutes and watch this.
Then make it viral. Please.