Jerry Rice, one of the NFL’s best receivers ever, is dancing. He starts this week as a contestant on the TV show “Dancing with the Stars.” “They approached my agent and we thought it would be something that would be interesting. It is something that really takes me out of my comfort zone and I felt like it would be very challenging. And that’s been true. It’s very challenging. It’s been more than I expected. Just because you have rhythm doesn’t mean you can ballroom dance and all of that stuff.”