On a daily basis I am either: walking, running, or biking into work. I commute this way into my office rain, sun, or snow and I have not taken the metro in over 2 years. I obviously never wear my dress clothes into work (even when I'm walking because I sweat like a pig) and always bring a small bag with my change of clothes in it. On some days, I bring my clothes into work the day before so that I may get in a ride at Haines Point or a long run before heading straight into work from my workout. I love these days because doing a long run and going straight to work as appose to going home first saves me so much time! And anytime I can sleep in longer is a positive in my book!
But, there is a downside to these commutes.... the fear of forgetting your dress clothes, under wear, bra, etc :( If you have a green commute you are bound to forget something sooner or later!