Les concerts à emporter, or Take Away Shows, are a project by La Blogotheque, a French site that features artists playing a show in a strange or unconventional location. Pitchfork has been posting a lot of them lately and they're really quite amazing. Some of the locations include wine cellars, a phonograph repository and a gallery. They feature both newer artists and more established acts. Perhaps the most interesting aspect is the type of acoustics the artists get in these locations.
The best I've seen so far was Local Natives, who performed "Who Knows, Who Cares" (pretty much my favorite song of theirs) in a gallery that echoed their vocals in a way that perfectly matched their style.