Run with friends
What it is, is an application for iPhone you can use to improve your health. This app is based on the trend sharing, which is about people wanting to include others into their lives in a new way (for example on the internet). With Run with friends you can include your friends by setting a goal for you and the other person to reacht (like running a mile). Others can also set a goal and include you on Facebook.
Why it is cool, is because this way you can get motivated by those close to you, and still do the actual running alone. For some, doing sports together is horrible, this way you can have both. You're not lonely but you can still do your individual sport.