For a month now, I've counted my steps using the pedometer built into my iPhone 6, with a daily goal of 10,000.
Sitting is deadly, and I've found that counting steps, combined with some positive peer pressure, makes me want to move more throughout the day.
Then get co-workers and friends to install it – that accountability and positive peer pressure does a lot, even if you feel that you're in it to challenge yourself, not others.
My gang has been running a "Weekend Warrior" challenge every Saturday–Sunday and a "Workweek Hustle" every Monday–Friday. Independent of any ongoing challenge, you can also see a "7 day steps" running top list among your friends.
You get push notifications if someone's catching up to you, cheers and comments in the challenge comment thread, and virtual badges when you reach new milestones. It's all quite fun and encouraging.
I like Pedometer++ (free, pay to remove ads) mostly because it can show my step count as a Notification Center widget, accessible by sliding down from the top of the phone's screen, even if the phone is locked. The app (not the widget) also provides step graphs, and a delightful confetti burst when you reach your daily goal.
You can see very clearly in the graph when I started counting steps:
You can also see that I might have gone a bit overboard the first weekend. You want to win the first one so you have nothing to prove later…
I've noticed interesting effects from having a step goal.
Since I'm pursuing a daily goal as well as challenging other people, walking becomes preferable to sitting or standing still. Waiting is no longer tedious; it's a chance to get some walking in. 10 minutes until the bus arrives? Excellent, that's 1,000 steps. Code discussion? Walk and talk.
Errands become opportunities. I used to dislike having to walk to the grocery store. Now I intentionally buy less milk every time so I have to go there more frequently. A weekend morning walk to buy breakfast can be lovely. Unexpected benefit: the fridge is less crammed.
I've explored new places. Walking further feels like a win.
At work, we've started taking lunch and afternoon walks. Many of us walk a bigger part of the way to work.
I quite like how the 10,000 step commitment means that a certain chunk of your day (around 100 minutes) has to be peripatetic. You can listen to podcasts, music, audiobooks, birdsong, city life; or talk to someone; or think. What you can't do is spend that time in a couch watching TV, or seated in front of the computer. It leaves slightly less room for sedentary life.