I've figured out a way to make going to the gym not only required but desired!!! I load my iphone with a great TV series (one with a few seasons that build on the last i.e. the Sopranos) and am only allowed to watch it while on the stairmaster. I tend to end my workout at a very suspenseful moment, insuring I will return the next day to watch the conclusion. I'll also download great songs/podcasts I'm only allowed to listen to while lifting weights.
Recommended TV shows during cardio: Sopranos, The Wire, Six Feet Under, Breaking Bad - you can buy them all on itunes.