Life without focus

My knee feels great. My cardio...not doing so well.  Last Saturday I was able to run 8+ miles (The Spokane Dirty Dash, plus running 2 miles from where I parked to only get to the start line 10 minutes late), but was dying the last 1/2 mile.  Why? I got do not have a serious running goal on my calendar.  I am the type of person that wishes they could just go out and run for running, a free runner. But I'm not at that point. I need a big goal looming over my head, if not, life will distract me. So this weekend, I am sitting down and finding my next big race to register to run.  I'm looking marathon and one that is about 6 to 8 months away.