Campnab - Nab that sold-out campsite!
Strava - The #1 app for runners and cyclists
Hipcamp - Book unique camping experiences on over 300,000 campsites, cabins, RV parks, public parks and more.
MyFitnessPal - Track the number of calories that you consume each day with MyFitnessPal. The app also lets you create a diet and track the exercise that you complete each day whether it's walking, running or some other type of program.
Campflare - Get notified when there are campsites open at your favorite campground. Its free.
Runtastic - Runtastic offers a series of fitness apps that can be used to track your running, walking, hiking, and cycling, as well as many other fitness routines. Read more about Runtastic.