In 1986, the United Way released 1,500,000 balloons in Cleveland, Ohio. It was supposed t just be a fun attempt at a World Record, but they ended up creating a nightmare for the entire community.
Source: Digg
A 34-year-old man got his parachute stuck on a parking garage and was hanging about 40 feet in the air when the police arrived to help him, and he ended up breaking both of his legs in the accident.
Source: ABC 5