Mumford & Sons, one of my favorite bands, has an official app, of course, this being the age of the smartphone.
Users can read up-to-date news from the band and check out posts from signed-up members of the app as well as from the band itself. Gentleman of the Road users can also find upcoming shows and venues, read posts from Mumford & Sons' Facebook page, see profiles of other members of the app, and then browse and (obviously) buy music from within the app, though it only links straight to the iTunes Music store.
In addition, there's a music player which will scan your iPhone for Mumford & Sons tracks you already own. Users can also write messages and include audio, video, photos in them, ostensibly to share Mumford & Sons concerts and sightings in real life.
Posts can be rated and then sorted with rating, highest viewed, and newest posts filters in the Wall and News sections, both accessed on the bottom tab bar.
Gentlemen of the Road is free, out now, and available in the App Store. If you're any kind of Mumford & Sons fan, you should probably check it out right now.