I had the pleasure of getting to know some new world class runners out here in Oregon and one small thing that we are starting to implement is this lunge routine. Check it, download the video, and do it every single day before every run. It's short but the athletes swear by it. LM - Lunge Matrix Video
This one is the full lunge warmup. So we now do the rope stretching and then this warmup everyday. LL - Lateral Lunge Video