Usually between a half mile and mile run as a warmup, dynamic stretches, and some shadowboxing to get loose.
For weights I'll do the run and the dynamic stretches before I begin, then before each exercise I'll do a few light sets to get the muscles warm and work all the kinks out.
"I don't want them to like me, because when I'm in the ring, punches fly to the face. It is not a tenderness time. I am not falling in love. And he knows that when the fight starts I am kicking faces."
- Wanderlei Silva