"On Friday, September 10th the Houston Astros and their fans will attempt to set a new world record for most people playing a song on the harmonica.
The world record event will take place immediately following the 7:05pm game against the Dodgers. 10,000 harmonicas will be handed out prior to the game and fans who stay after the game will be taught how to play a song and a new world record will be set!
A Guinness Book of World Records representative will be present to verify the record and the number of people playing. Be a part of history!"
(via The Biz of Baseball)