1. Gigbox (Free)
An ideal app for concert lovers, Gigbox notes your current location and tells you when your favorite artist is playing a gig near you. Conveniently, it pulls in all your favorite bands and songs from your Last.fm account, and uses Google Maps to provide directions to venues.
Getting to the gig is only half the fun, as during the concert you can enter the app's live mode to chat and share pictures with other concertgoers around you. You can also rate the gig and get the current "mood" of the crowd. All of your chats and pictures are stored online as well, so you can go back through them and relive the experience at any time.