I completed my third 5K race in 2011.  It's been a real eye opening experience.  I have never considered myself a runner and haven't really ran until this year and have found that running is one of the best exercise experience (second to biking).  I am now training for a half marathon in late fall and hoping to run a personal best time as well.  Running is a great stress reliever.  Instead of impulse purchases and emotional eating, just going for a run provides a nice break from daily stressors.