I love TV. I can sit and watch it for hours. I know that this isn't good for my body, but I don't think anyone should completely abandon all of the things they enjoy for fitness. Fitness should fit into your life, not make your life unrecognizable. At least not overnight. Over a long time, gradual changes can erode old habits and totally change your life into something completely different from what it was a few years earlier.
Before those huge changes occur, there are ways to fit fitness into your life as it currently exists. I like TV and have found ways to work out while watching TV. For some people that means running on a treadmill while watching their favorite shows. I use my bike trainer while watching shows that I want to see, but don't love. That way I'm not upset if I miss something with the noise of the trainer.
I found two workouts on Pinterest today that are specifically designed for getting in some fitness while watching TV. One is the "How I Met Your Mother" workout. It has 20 exercises, one for each minute of the show. This would work for any sitcom that is about 20 minutes long, not counting commercials. All of the exercises are standing, so you won't have to take your eyes off the television. This has the added benefit of encouraging you to keep your posture steady, instead of lazily looking at the ground.
The other workout is the TV Commercial workout. It is just a list of advertisers and a corresponding exercise to do when they're the commercial currently airing. It's a great concept, though. You could change up the list and tailor it to the type of programming you're watching. If you don't want to jog all the time, you may want to split the cars into foreign/domestic during sports.