Stretch for 10 minutes. Skip for 5 minutes. Jog for 10 minutes. Run for 10 minutes. Walk back. Do 50 crunches. Being lazy might feel good at the time, but being active feels better in the long run. How badly do you want it?
Challenging runners treadmill workout--said it will flatten your belly, slim your thighs, and firm your butt in 2 weeks--without a single sit-up or squat--there is a link to a beginners runners workout too