As previously covered in these pages, the Pitch Drop experiment involves setting up a funnel of highly viscous pitch (which is 2 million times more viscous than honey) and waiting for it to form a drop. It takes between 7 - 13 years for a single drop of pitch to form and drip out of the funnel. Despite two separate Pitch Drop experiments running in Dublin and Australia, since 1944 and 1927 respectively, no drop has ever been actually been witnessed falling (the last drop, which fell in 2000 from the Australian experiment, was missed thanks to a malfunctioning webcam).
However, on July 11, 2013, the elusive drop was finally caught on film. Head over to RTE.ie to watch the actual video.