On the Treadmill

I don't know about you, but I find going to the gym really quite a challenge - a Gym-bunny I am not...! Don't get me wrong, I do a lot of exercise, I generally play football for two hours a week and mostly with lads half my age - my problem is that I love team sports, but am uninspired when it comes to jumping on treadmills or cycling/rowing machines and what have you.
However, I reckon I could get into it if I had some of my own exercise equipment in the house so I could pop in and do a bit when I have half-an-hour or so to spare.
I would be particularly inspired if the exercise could be set up in such a way that I had a challenge to rise to when using a treadmill or some other gym equipment - I can't just go and do 'reps' and see that as a challenge on it's own - I need some real motivation!