A simple, powerful mashup is the best thing to happen to music on the internet in a little while.
Gigfi bills itself as "your local playlist." Which sounds like whatever, but this simple premise delivers a legitimately cool music experience: Tell Gigfi a city or a venue, and it spits out a grid of artists coming to said location in the near future, along with a handy custom Spotify playlist featuring a selection of songs from each of the artists.
It's pure music multitasking — you get to see and hear the artists coming to your area without having to keep up with local listings, and it takes a lot of the work out of finding new music to listen to. Plus, if you hear something you like, you know the band's on its way to your town, and you can find tickets straight from Gigfi's site.
Even the way it works is deceptively simple: Gigfi uses last.fm's listings to find upcoming concerts, and then plugs that data into Spotify to create a playlist. You obviously need Spotify to use it, but fortunately Spotify's free if you can deal with hearing the occasional ad, so there's no reason for you to not spend the rest of Friday afternoon listening to Gigfi.