When I do the elliptical at the gym, I wear my iPod and play my "hard workout" playlist. It has songs by Metallica, Godsmack, Rob Zombie--all heavy, driving, fast songs. I change tempo and resistance with each song. The playlist is also on "shuffle" so there's no way to predict which song I'll get next. It keeps it interesting.
On the treadmill at home, I am set up behind the couch (which is in front of the tv). Instead of just "walking-walking-walking-BORED NOW!" I do 10 minutes on the treadmill, then a round of upper body/ab exercises, then 10 more minutes, then another round, etc. I'll do that while 'watching' shows like Celebrity Fit Club 2 (which sadly has finished now), The Biggest Loser 2 (just started!), and House (medical drama).
Sometimes if the treadmill is truly a revolting concept (hey, it happens) I'll just go ride my bike or wander around my neighborhood. The key is to have options, and to explore different things that work for you. I've been exercising consistently for 15 years (yeah, I'm one of those 'fat but fit' people) and you really do get to the point where it's something your body craves. Patience and options are the keys.
