Maurizio, thanks for the info.
Let me clarify my original question for dualman. I probably exercise more than everybody who has posted here except Maurizio (my roommate is a competitive cyclist, so I know you're working your a$$ off). My point was, unlike Maurizio, I don't have a desire to be a competitive runner or cyclist. If I run 30 miles a week, yes, it gets boring. There aren't many great areas to run on streets around here, so pretty much my only option is a track at the local high school. I'm willing to bet you've never run 30 miles in a week dualman, and especially not around a track.
xyzzy, when I'm on the exercise bike I'm working my butt off. I have access to a bike that monitors heart rate, so I can cardio train and make sure I'm not getting lazy - I try to keep my heart rate at about 160, so it's definitely not easy. I thought I was sweating a lot when I was pushing 170 yesterday, I can't imagine doing 200+. But yes, watching TV is motivating. If there is a game on and I can watch it for an hour while riding the bike, I'm more likely to do that than run 6 miles. That's why I was asking about the benefits of the bike vs. running.
I'm also looking for other ways to get a good cardio workout. I mentioned racquetball because I can play for a few hours and be just as tired as when I run 6 miles. I'm not the type that just hits the ball toward the wall when it comes my way - we're pretty intense. I was hoping somebody knew of another activity that could give me similar results so I don't have to play the same guy in racquetball as my only break from running.
I do cardio 6-7 days a week, so it's not like I'm looking for an easy way out. I've been doing a lot of running, that's why I'm looking for new ways now. Thanks for the replys (except for dualman).
Let me clarify one more thing from my original post - when I say riding the bike is easier than running I mean easier on the body (especially the knees).