Want to track that run, hike, or bike ride? Look no further. One of the most popular fitness-tracking apps, RunKeeper lets users track distance, length, and calories for their workouts and then share and compare stats on social media. The company recently released a sleek redesign that allows for easier photo sharing and faster updates. (Plus it’s super pretty.) And non-iPhone users, don't fret; they've got an Android app, too.