Sign up for an up coming 5km, 10km event or even a half-marathon. I find working towards a tangible event makes me get off my couch and go outside to train. I have been training for an upcoming half-marathon (my first) and I am really doing well. I can now do 8.5km 4 days/week pain free!
look for upcoming races/events in your area - usually you can pre-plan 6-8 months prior to the event if it is a yearly event.