The world’s oldest playable organ: Notre-Dame-de-Valère at Sion (Switzerland)
The slideshow in the linked article has a cool shot of the bellows.
This page on Organ Oddities mentions that the St. Andreas at Ostönnen organ in Westfalia, Germany may be older. Specifically, “the Ostönnen organ is older in terms of acoustics but the Sion one in its optical appearance.”
The slowest piece of organ music in the world: composed by John Cage – “ASLSP” – “As slow as possible”. It is still in progress and is supposed to last over 600 years! Apparently it’s a really big deal when they add a pipe or change a note:
In 1985 John Cage (USA, 1912-1992) wrote a piece for piano which in 1987 he transcribed for organ, “ASLSP” – “As slow as possible”.
In 1997, during an organ symposium in Trossingen (Germany), a group of organists, artists, organbuilders, theologians and philosophers had the idea to take this title literally and perform the piece over a period of more than 600 (!) years.
The only instrument that could be considered for such a performance was the organ. So specifically for this project Romanus Seifert & Son organbuilders (D, Kevelaer) built an organ that will grow along with the project. The first chord was struck on February 5, 2003, the next changes of tone are scheduled for November 5, 2008 and February 5, 2009. The final tone is said to be sounded in 2639.
Update: I cannot believe the coincidence of this. After I wrote about John Cage’s “ASLSP”, I picked up a Pittsburgh City Paper and saw that Pleasant Hills Community Presbyterian Church is launching its Lenten Concert Series with a five-hour performance of the piece, by organist Robert Morehead. What are the odds of me learning about the existence of this composition in the morning and then reading about it in the paper later the same day?!?!?! It’s so bizarre that I could discover such a weird thing and coincidentally be able to go see a performance of it, without having to travel to Germany. WOW.