I know what everyone says about finding new routes and spicing up your running and everything, but...
What really has worked for me at times when I've felt burnt or impending burnout is: Reducing the number of running routes.
When I lived near to where I used to go to college, I ended up running up ~80% of my weekly milage (between 65-120 miles/week at that time) around a trail loop of 2.3 miles. Sometimes I added on around the athletic fields and such too. Whenever I started feeling burnt I'd often notice that I had been running all over the place a lot, and by re-focusing upon that loop for most of my running, I'd feel better in a jiffy.
Now I live in a far different place, and I have miles and miles of trails around, and a lot of county roads and parks to run about. What is working best for me, however, is doing the majority of my runs over three different routes. A 13 mile course between work and home, a 3 mile dirt loop, and a 20+ mile meandering hilly dirt route for long runs.
I've been thinking about this a bit, and I have a few theories as to why this has worked for me.
1) By running the same small loop over and over again, I can become more in touch with the small variations in how my body is feeling, and thus react to them more promptly.
2) Maybe after doing the same same routes so much of the time, when I finally hit out on a new route it's much more of a refreshing treat.
3) Maybe trying to decide where to run every time I'd go out the door would take too much mental energy--maybe this is an big advantage of the Australian Complex Training system such as used by DeCastella... don't have to think too much about what you're going to do.
Well, I've lost my train of thought.
Maybe give it a try