I watched. I cheered. I forgot to wear some pink (thought about toting the nearly-empty pink water bottle from my car though!). I ran the final stretch with them, outside the barrier. (People probably thought I didn't understand the nature of the race course.) I fought back a few tears, especially seeing the runners with "In Memory Of" signs taped to their backs.
Next year, I'm hoping to run. Maybe with an "In Celebration Of" sign on MY back.