This one has been around for years, and is one of my favorites. I love the way she kicks as hard as possible, but just laughs at him after. She says he deserved that, I hope he did, because she really nailed him.
It doesn't really look like she connected with his balls, but still cool...
Every time I see vids like that, I just hope it's a back and forth thing between them, because if he posted a video of him punching her in the tit as hard as he could people would be screaming for his head on a stick.
It was supposed to be her revenge for this: http://youtu.be/TMiVNZOqXe4
It's a great video, but it's staged (I only mention that because a lot of people seem disturbed by it).
This couple is still popular on youtube, but they mostly do vlogs about the married life.
They seem to be happy.