We’ve recently discovered a very awesome project by UK artist Luke Jerram called Sky Orchestra. Jerram attaches very loud speakers to 7 hot air balloons and then sends them up to hover above a city. Each speaker plays a certain part of a song composed by Dan Jones, creating surround sound in the sky! It’s sort of like a hot air balloon version of Zaireeka. The project has been going on since 2003. The above video is from Switzerland in 2005. Here’s one more video from the Sydney version in 2007.