Look at you - going for a run without a gizmo to track your progress and bother your friends on Facebook. Lame, right? Well grab your sneakers, because the Nike+ app had landed in the Play Store, and it's free.
The app connects you to nikeplus.com, which acts like a portal for all the social features in Nike+, as well as a larger interface to check out your run data. There is no additional hardware needed to use Nike+. Just load up the app, and it uses your phone's GPS and accelerometer to record your pace, distance, and time. All that data gets fed into Nike+ and aggregated so you can enjoy some data porn later on.
Some handy features include a home screen widget that reminds you how lazy you are by displaying your total mileage and when you last ran. The PowerSong feature lets you crank your best tunes when you need a little more motivation. That's great if you're into 80's sports training montages set to Eye of the Tiger (like I am).
The app itself is fairly attractive, but doesn't really go in for the Holo UI scheme. It will pull up the legacy menu button on ICS devices. Remember that pinging the GPS and accelerometer will eat up battery life, and adding social content over wireless data to that is likely to worsen matters. Keep a spare battery handy.